Mix with people of the criminal kind (7)
I believe the answer is:
consort
'mix with people of' is the definition.
I can't judge whether this defines the answer.
'criminal kind' is the wordplay.
'criminal' becomes 'con' (abbreviation for 'convict').
'kind' becomes 'sort' (synonyms).
'con'+'sort'='CONSORT'
'the' acts as a link.
Can you help me to learn more?
(Other definitions for consort that I've seen before include "A monarch's spouse" , "helpmate" , "Keep company" , "Companion; ship sailing with another" , "Spouse, partner" .)