Addendum

For the sake of completing the concept explained in this sicha (section 7) — that Rashi writes the word ‘deficient’ only when dealing with a matter of deficiency — the following are the places where Rashi explains the reason for deficient spellings, in the order of the verses:

1. Parshas Bereishis 1:14: “‘Let there be מְאֹרֹת {luminaries}’ — Written deficient of vav because it is a יוֹם מְאֵרָה {cursed day}...” — indicating deficiency (as explained in section 7).
2. Parshas Bereishis 1:28: “‘וְכִבְשֻהָ {And subdue it} — deficient of vav — this teaches that the male subdues the female so she should not be wayward...” — because her mind is light (unlike the male) and she could be harmed — a matter of deficiency.
3. Parshas Bereishis 1:21: “‘The great הַתַנִינִם {sea monsters}” — He created them male and female, and He killed the female and preserved her for the righteous in the future era. For if they were permitted to reproduce, the world could not have endured in their presence. Therefore ‘הַתַנִינִם’ is written” — a virtue (as explained in section 7).
4. Parshas Bereishis 6:2: “‘That they were טֹבֹת {good}’ — Rabbi Yudan says טֹבֹת is written, for when they would beautify the bride {to enter the marriage canopy}, the head ruler would then enter {and have relations with her first}.” Although seemingly this verse refers to a deficiency, nevertheless: (1) This is Rabbi Yudan’s language, not Rashi’s. (2) When “the sons of the rulers saw...” — the brides were not “deficient” {of virtue}. [Indeed, this was the greatest virtue — that until the head ruler would enter, {they would remain chaste} out of modesty (note Rashi on Parshas Chayei Sarah 24:16). Therefore, Rashi must provide this explanation, in line with pshat, and not write “deficient” — which would indicate that they were immodest.] However, they knew that their end would not be good. (3) The name “יודן” is also written lacking a vav, and emphasizing “written deficiently” would thus be disrespectful.
5. Parshas Noach 8:21: “‘מִנְעֻרָָ֑יו {from his youth}’ — “מִנְעֻרָָ֑יו is written {indicating that} מִשֶּׁנִנְעַר {from when he begins stirring} to leave his mother’s womb, the evil inclination is placed within him” — this is a virtue, a defense of mankind (as explained in section 7).
6. Parshas Noach 9:12: “‘לְדֹרִֹ֖ ת {for all generations} to come’ — written deficiently, because there were generations that did not need the sign because they were completely righteous...” — a deficiency in “all generations to come,” because the term “all generations” does not include the generation of Chizkiyahu, etc.
7. Parshas Lech Lecha 14:14: “‘חֲנִיכָו {his trained men’ — It is written as חֲנִיכוֹ (missing a yud — singular} because this refers to Eliezer, whom he חִנְכוֹ {trained} to observe mitzvos” — a matter of virtue (see footnote 44 in the original sichah).
8. Parshas Vayera 18:1: “‘And he יֹשֵב {was sitting} at the entrance of the tent in the heat of the day’ — יֹשֵב is written... ‘You will symbolize to your descendants that I will stand in the assembly of judges and they will be sitting’” — a virtue emphasizing Avraham’s honor and stature, and the honor of the Jewish people.
9. Parshas Vayera 19:1: “‘And Lot יֹשֵב {was sitting} — יֹשֵב is written — that very day they appointed him as judge” — a virtue, because it clarifies that all of Sodom’s conduct until then was not his fault.
10. Parshas Chayei Sarah 23:10: “‘And Ephron יֹשֵב {was seated} — written deficiently, that very day they appointed him as officer...” — a matter of deficiency, since without Avraham needing him, he was not worthy of this (as explained in section 7).
11. Parshas Chayei Sarah 23:16: “‘And Avraham weighed out לְעֶּׁפְרֹֹ֔ן {to Ephron} — deficient of vav, because he promised much but did not even do a little” — a deficiency.
12. Parshas Chayei Sarah 24:39: “‘אֻלַי {Perhaps} the woman will not follow me’ — it is written as אֵלַי {to me} — for Eliezer had a daughter, and he was hoping to find a reason for Avraham to turn to him to marry his daughter” — a virtue regarding Eliezer and his daughter, for if not for the sin of “Cham” [through which he became a slave — “cursed”, and consequently, “a cursed one cannot cleave to a blessed one”], they would be worthy for Yitzchak.
13. Parshas Chayei Sarah 25:6: “‘הַפִִּֽילַגְשִם {the concubines}’ — written deficiently, because there was only one concubine” — the most obvious case of deficiency: where the word “הַפִִּֽילַגְשִ ים” (plural) refers to only one.
14. Parshas Toldos 25:24: “‘And behold תוֹמִם {twins}’ — deficient — one was righteous and one was wicked” — a deficiency.
15. Parshas Vayeshev 38:27: “‘תְאוֹמִים — spelled in full, whereas later the Torah states תוֹמִים — deficient, because one was wicked” (as in #14 above).
16. Parshas Shemos 3:15: “‘This is My Name לְעֹלָם {forever}’ — deficient of vav, to teach us to conceal it — that it {Hashem’s name} should not be read as it is written” — the most obvious deficiency.
17. Parshas Mishpatim 23:2: “‘You shall not respond עַל רִ ב {concerning a dispute}’ — meaning, עַל רַב {against the elder}, that one should not disagree with the most distinguished member of the court” — a matter of virtue. [Only at the end of his commentary does Rashi note how we learn this: “because it is missing a yud they interpreted it this way.”]
18. Parshas Ki Sisa 31:18: “‘כְכַלֹּתוֹ {When he finished} speaking with him — It is written as כְכַלָתוֹ... like a כַלָה {bride} to a bridegroom” — a virtue and advantage in the giving of the Torah.
19. Ibid: “‘לֻחֹת is written, indicating that they were both equal” — a virtue (as explained in sections 8ff).
20. Parshas Vayakhel 35:27: “‘וְהַנְשִאִם {the leaders}’ — Because they acted with an element of laziness, a letter was omitted from their name” — a matter of deficiency.
21. Parshas Emor 23:40: “‘כַפֹת {branches}’ — deficient of vav, teaching that it should be only one” — the most obvious case of deficiency: where “כַפֹ ות” (the plural form of the word) refers to only one.
22. [Parshas Naso 7:1: “‘When Moshe תֹּ לַּ כ {completed}’ — It is written as תַּ לַּ כ — for when the Mishkan was erected, the Jewish people were like a bride entering the marriage canopy” — a virtue and completion in the erection of the Mishkan for the Jewish people.]
23. Parshas Naso 7:19: “‘הִקְרִ ב {he offered} his sacrifice’ — deficient of a yud, implying הַקְרֵב, ‘you shall bring forward!’ — the imperative usage” — a matter of deficiency, since there was a challenge requiring a special command.
24. Parshas Shelach 15:24: “‘לְחַטִָּֽת {as a sin offering} — deficient of an aleph, for it is different from other sin-offerings where the sin-offering precedes the burnt-offering when they come together,... but this burnt-offering precedes the sin-offering” — a deficiency in this sin-offering compared to other sin-offerings.
25. Parshas Balak 22:5: “‘and it has יֹשֵב {settled} next to me,’ — written deficiently. {Meaning:} ‘they are nearby, to cut me down’” — a matter of deficiency regarding Balak, his entire existence would be lacking.
26. Parshas Devarim 1:13: “‘וַאֲשִמֵם {And I will appoint them} as your heads’ — deficient of a yud: This teaches that אַשְמוֹתֵיהֶּׁם {the transgressions} of Israel are attributed to their judges” — a matter of greatness (“and I will appoint them as your heads”) and its opposite (their faults — “‘וַאֲשִמֵם deficient of yud,” meaning אַשְמוֹתֵיהֶּׁם {their transgressions}, etc.)
27. Parshas Devarim 2:33: “‘And בָנָו His sons’ — It is written as בְנוֹ {his son — singular} because he had a son who was as mighty as he” — an additional emphasis in the similarity of his son to him, that he was as mighty as him. (This also emphasizes the Jewish people’s greatness, who destroyed him and his sons, notwithstanding their great strength.)
28. Parshas Vaeschanan 6:9: “‘מְזֻזוֹת {the doorposts}’ — מְזֻזוֹת is written, because only one is needed” — a virtue in the mezuzah, that no additional mezuzah is needed on this doorway (see Be’er Mayim Chaim, Maskil LeDavid, et al.), since one mezuzah on the doorway fulfills its function completely.
29. Parshas Eikev 9:11: “‘לֻחֹת’ is written, indicating that they were both equal” — a matter of virtue (as explained in sections 8 ff).

There is more to be said about several of the above, but this is not the place.