More endearing quality? Or lack of one? (7)

I believe the answer is:

absence

I'm a little stuck... Click here to teach me more about this clue!

'lack of one?' is the definition.
'absence' can be an answer for 'lack' (I've seen this in another clue). I'm not certain of the 'of one?' bit.

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for absence that I've seen before include "Want, lack" , "Non-attendance" , "Want (of something)" , "What supposedly makes the heart grow fonder?" , "what can be heart-warming?" .)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.