Turning on crazy wanderer (5)
I believe the answer is:
nomad
'wanderer' is the definition.
(nomad is a kind of wanderer)
'turning on crazy' is the wordplay.
'turning' is a reversal indicator.
'crazy' becomes 'mad' (synonyms).
'on' back-to-front is 'no'.
'no'+'mad'='NOMAD'
(Other definitions for nomad that I've seen before include "A wandering tribesman" , "Person wandering" , "being domestically unstable" , "Roamer" , "one of those with no fixed home" .)