Mean to split the rent with a colleague (7)
I believe the answer is:
partner
'a colleague' is the definition.
(I've seen this before)
'mean to split the rent' is the wordplay.
'mean' becomes 'par' (I've seen this before).
'to split' indicates anagramming the letters (letters split up and reassembled).
'rent' anagrammed gives 'tner'.
'par'+'tner'='PARTNER'
'with' acts as a link.
(Other definitions for partner that I've seen before include "Business colleague" , "south to north, perhaps" , "Either one of a couple" , "Colleague, bedfellow" , "Husband or wife" .)