Proposal from assassin? (5)
I believe the answer is:
offer
I believe this is a double definition.
'proposal' is the first definition.
(I've seen this in other clues)
'assassin?' is the second definition.
(someone who 'offs' people)
'from' acts as a link.
(Other definitions for offer that I've seen before include "Submit" , "Present for acceptance or rejection" , "(Suggestion of) gift" , "Hold out, tender" , "Propose; make available" .)