Fellows gather round to help a girl (6)
I believe the answer is:
maiden
'a girl' is the definition.
(I know that maiden is a type of girl)
'fellows gather round to help' is the wordplay.
'fellows' becomes 'men' (fellow can mean a man).
'gather round' is an insertion indicator.
'to help' becomes 'aid' (synonyms).
'men' enclosing 'aid' is 'MAIDEN'.
(Other definitions for maiden that I've seen before include "clothes horse" , "Of an aunt, unmarried" , "Damsel" , "Unmarried girl of old" , "When you get her" .)