Resilience of black cat (6)
I believe the answer is:
bounce
'resilience' is the definition.
(thesaurus)
'black cat' is the wordplay.
'black' becomes 'b' (as in pencil classifications).
'cat' becomes 'ounce' (ounce is a kind of cat).
'b'+'ounce'='BOUNCE'
'of' is the link.
(Other definitions for bounce that I've seen before include "Rebound (of ball)" , "Rebound (like a cheque)" , "What a cheque may do if there are insufficient funds" , "Of a cheque, send back as worthless" , "Spring back like a rubber ball" .)