Your compiler is offensive but cool (10)
I believe the answer is:
impersonal
'cool' is the definition.
(cool can mean impersonal or distant)
'your compiler is offensive' is the wordplay.
'your compiler is' becomes 'I'm' (referring to the crossword compiler).
'offensive' becomes 'personal' (eg a personal question is offensive).
'im'+'personal'='IMPERSONAL'
'but' is the link.
(Other definitions for impersonal that I've seen before include "Aloof" , "Ignoring one's own feelings" , "Cool" , "Cold" , "Objective; disinterested" .)