Ordinary coarse fish dive around men (6-2-6)
I believe the answer is:
common-or-garden
'ordinary' is the definition.
(I've seen this before)
'coarse fish dive around men' is the wordplay.
I cannot really see how this works, but
'coarse' could be 'common' (synonyms) and 'common' is present in the answer.
'fish' could be 'gar' (type of gar) and 'gar' is found within the answer.
'dive' could be 'den' (I've seen this in other clues) and 'den' is found within the answer.
'around' could be 'o' (I've seen this in other clues) and 'o' is located in the answer.
A single letter 'r' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
(Another definition for common-or-garden that I've seen is " Ordinary".)