Men returning caught enormous bird (3)
I believe the answer is:
roc
'enormous bird' is the definition.
(I've seen this before)
'men returning caught' is the wordplay.
'men' becomes 'or' (I've seen this in other clues**).
'returning' says the letters should be written backwards.
'caught' becomes 'c' (cricket abbreviation).
'or' in reverse letter order is 'ro'.
'ro'+'c'='ROC'
(Other definitions for roc that I've seen before include ".Fabulous bird of the East" , "Bird imagined" , "Cor! what a fabulous bird" , "Big bird" , "Mythical creature from Arabia" .)