Equal rent negotiated for colleague (7)
I believe the answer is:
partner
'colleague' is the definition.
(I've seen this before)
'equal rent negotiated' is the wordplay.
'equal' becomes 'par'.
'negotiated' indicates anagramming the letters.
'rent' anagrammed gives 'tner'.
'par'+'tner'='PARTNER'
'for' is the link.
(Other definitions for partner that I've seen before include "sometimes joining in crime" , "Accomplice" , "Confederate" , "Mate or business associate" , "Business colleague" .)