Chap’s dropping masculine woman (3)
I believe the answer is:
ada
'woman' is the definition.
'chap's dropping masculine' is the wordplay.
'chap' becomes 'ad'.
'dropping masculine' becomes 'a' (I can't explain this - if you can you should believe this answer much more).
'ad'+'a'='ADA'
Can you help me to learn more?
(Other definitions for ada that I've seen before include "girl?" , "Girl's name, one letter short of a man's name" , "Computer language; girl's name" , "Palindromic girl's name" , "Novel by Vladimir Nabokov" .)