The meta answer is PITY (Hint: Find a 4-letter noun.)
Four of the long Across answers end with syllables that sound like plurals of letters of the alphabet:
FLYINGTRA(PEZE) = Ps
JEOPARD(IZE) = Is
STRIP(TEASE) = Ts
TURNCLOCK(WISE) = Ys
This is where the puzzle's title, "Singular Kindness" comes into play. When you make those plural letter sounds "singular," you get P, I, T, and Y--which spells PITY, a 4-letter noun meaning "kindness" that satisfies the puzzle's hint.
Meg 2s · 2024-12-08T01:29:15.280Z
Very nice!! I think the clue for 71a should read "Stimulates".
I had to reveal because I got caught in a rabbit hole of my own making. I saw the PEZE, etc. and KNEW that those endings could not be by chance but was SURE that TURNCLOCKWISE was a nudge clue and that I would have to turn the page. Doin that gave me two Ns (Zs turned 90 degrees clockwise and an O but I could not find the other letter that would appear when I turned the grid. Once again, nothing wrong with the puzzle, just the solver.