Hardly a crazy rambler (5)
I believe the answer is:
nomad
'rambler' is the definition.
(someone who roams or rambles)
'hardly a crazy' is the wordplay.
'hardly' becomes 'no' (eg 'hardly a meal' means 'not a meal' or 'no meal').
'a crazy' becomes 'mad' (I've seen this in another clue).
'no'+'mad'='NOMAD'
(Other definitions for nomad that I've seen before include "Unsettled character" , "Person always on the move" , "Roamer" , "Member of a wandering pastoral community" , "someone who can't settle" .)