A female or a small male (3)
I believe the answer is:
she
'a female' is the definition.
('she' refers to a woman)
'a small male' is the wordplay.
'a small' becomes 's' (abbreviation - e.g. clothes size).
'male' becomes 'he' (he refers to a man).
's'+'he'='SHE'
'or' is the link.
(Other definitions for she that I've seen before include "Book" , "way to refer to mare" , "The one who must be obeyed" , "H. Rider Haggard novel" , "1887 Rider Haggard novel" .)