Partner is criminal type (7)
I believe the answer is:
consort
'partner' is the definition.
(I know that consort is a type of partner)
'criminal type' is the wordplay.
'criminal' becomes 'con' (abbreviation for 'convict').
'type' becomes 'sort' (both can mean a kind or variety).
'con'+'sort'='CONSORT'
'is' acts as a link.
(Other definitions for consort that I've seen before include "A monarch's spouse" , "Habitually associate (with)" , "Companion; ship sailing with another" , "Small group; spouse" , "Group playing music" .)