A means to get off (4)
I believe the answer is:
away
'off' is the definition.
(synonyms)
'a means' is the wordplay.
'means' becomes 'way' (a way or means of doing something).
'a'+'way'='AWAY'
'to get' is the link.
(Other definitions for away that I've seen before include "Not at home, somewhere else" , "Chelsea's game at Old Trafford is" , "Departed" , "football result!" , "Onward" .)