Vagrant Mike into gin (5)
I believe the answer is:
tramp
'vagrant' is the definition.
(I know that tramp is a type of vagrant)
'mike into gin' is the wordplay.
'mike' becomes 'M' (phonetic alphabet: alpha, bravo, charlie etc.).
'into' indicates putting letters inside.
'gin' becomes 'trap' (I've seen this in another clue).
'm' inserted into 'trap' is 'TRAMP'.
(Other definitions for tramp that I've seen before include "I usually walk" , "sometimes harboured?" , "man down on his luck" , "Live as a vagrant" , "Walk heavily, as when weary, or through mud" .)