Brute having a bit of fun sorting the mail (6)
I believe the answer is:
animal
'brute' is the definition.
(I know that brute can be written as animal)
'a bit of fun sorting the mail' is the wordplay.
I cannot quite see how this works, but
'a' could be 'an' and 'an' is found within the answer.
'bit' could be 'i' (resembles 1, a binary digit or bit) and 'i' is located in the answer.
The remaining letters 'mal' 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).
'having' acts as a link.
Can you help me to learn more?
(Other definitions for animal that I've seen before include "lamb, perhaps" , "cat, perhaps" , "Living creature with voluntary motion" , "Circus performer, maybe" , "Such as 13 ac" .)