American criminals smuggling heroin back from Alaska, possibly (7)
I believe the answer is:
perhaps
'possibly' is the definition.
(synonyms)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for perhaps that I've seen before include "Could be, maybe" , "It may be" , "Quite possibly" , "Possibly but not certainly" , "Conceivably" .)