An offer a month short in Ivory Coast city (7)
I believe the answer is:
abidjan
'ivory coast city' is the definition.
(I've seen this before)
'an offer a month short in' is the wordplay.
'an offer' becomes 'bid' (bid is a kind of offer).
'month short' becomes 'Jan' (Jan is short for January; 'short' asks for an abbreviation).
'in' means one lot of letters goes inside another.
'a'+'jan'='ajan'
'bid' put within 'ajan' is 'ABIDJAN'.
(Other definitions for abidjan that I've seen before include "Ivory Coast city" , "Ivory Coast port" , "African city" , "Former capital of Ivory Coast" , "African port" .)