Didn't cry over having no rent (8)
I believe the answer is:
tearless
'no rent' is the definition.
Both the definition and answer are adjectives. Maybe there's an association between them I don't understand?
'didn't cry over' is the wordplay.
'didn't' becomes 'less' (I can't explain this - if you can you should give a lot more credence to this answer).
'cry' becomes 'tear' (tearing is a kind of crying).
'over' says to put letters next to each other (in a down clue, some letters go over others).
'less' after 'tear' is 'TEARLESS'.
'having' acts as a link.
Can you help me to learn more?
(Other definitions for tearless that I've seen before include "without displaying sorrow" , "stiff upper lip" , "betraying no emotion" , "Dry" .)