Against being included by clever suspect (6)
I believe the answer is:
versus
'against' is the definition.
(as in one sports team versus another)
'included by clever suspect' is the wordplay.
'included' indicates a hidden word (I've seen 'including' mean this).
'VERSUS' is hidden within 'by clever suspect'.
'being' acts as a link.
(Other definitions for versus that I've seen before include "Against in games" , "Against (another team)" , "v. (sport)" , "Set against" , "In opposition to" .)