Young lady’s assistance accepted by some guys (6)
I believe the answer is:
maiden
'young lady's' is the definition.
(maiden is a kind of young lady)
'assistance accepted by some guys' is the wordplay.
'assistance' becomes 'aid' (synonyms).
'accepted by' indicates putting letters inside (inserted letters are accepted).
'some guys' becomes 'men' (guy can mean a man).
'aid' placed into 'men' is 'MAIDEN'.
(Other definitions for maiden that I've seen before include "Six dot balls" , "I named (anag) - young woman" , "No runs are scored from this - young girl" , "Ship's first trip" , "horse that's never won" .)