Greek character goes about with fools (4)
I believe the answer is:
mugs
'fools' is the definition.
('mug' can be a synonym of 'fool')
'greek character goes about' is the wordplay.
'greek' becomes 'G' (philological abbreviation).
'character' becomes 'mus' (I can't justify this - if you can you should believe this answer much more).
'goes about' is an insertion indicator.
'g' inserted within 'mus' is 'MUGS'.
'with' is the link.
Can you help me to learn more?
(Other definitions for mugs that I've seen before include "Robs with the threat of violence" , "Gullible people" , "fools and > grimaces" , "'Cups, faces and fall guys (4)'" , "Attacks" .)