A small male or a female (3)
I believe the answer is:
she
'a female' is the definition.
(I've seen this before)
'a small male' is the wordplay.
'a small' becomes 's' (abbreviation - e.g. clothes size).
'male' becomes 'he' ().
's'+'he'='SHE'
'or' is the link.
(Other definitions for she that I've seen before include "Rider's novel" , "1887 Rider Haggard novel" , "That woman" , "Female person" , "- - Loves You (Beatles)" .)