Catch business associate mostly lying around (6)
I believe the answer is:
entrap
'catch' is the definition.
(to entrap is to catch with a trap)
'business associate mostly lying around' is the wordplay.
'business associate' becomes 'partner' (business partner).
'mostly' means to remove the last letter (most but not all of the word).
'lying around' is a reversal indicator.
'partner' with its last letter taken away is 'partne'.
'partne' back-to-front is 'ENTRAP'.
(Other definitions for entrap that I've seen before include "Deceive -- lead on" , "Snare, trick" , "Snare - inveigle" , "Trick or beguile for parent" , "Set up" .)