She doesn't look so cocky as her mate (6)
I believe the answer is:
peahen
'mate' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'she doesn't look so cocky as her' is the wordplay.
I cannot quite understand how this works, but
'she' could be 'hen' (I've seen this before) and 'hen' is found in the answer.
The remaining letters 'pea' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for peahen that I've seen before include "Drabber female of a spectacular bird" , "Female of the large bird, Pavo species" , "Drab bird" , "Female bird (with a proud partner?)" , "Female of a show-off bird" .)