Girl's (6)
'girls' is the definition.
(lass can informally mean a girl)
This is the entire clue.
(Other definitions for lasses that I've seen before include "Lads and - -" , "Northern girls?" , "Young ladies" .)
'girl's' is the definition.
('her' refers to a girl or woman)
This is all the clue.
(Other definitions for her that I've seen before include "Belonging to the woman" , "In the Midlands she" , "That lady's" , "That lady" , "The female's" .)
(Other definitions for les that I've seen before include "-- Dawson, English comic" , "-- Dawson (late comedian)" , "Short boy or girl" , "-- Miserables, musical" , "French article; name" .)