Turning on crazy wanderer (5)
I believe the answer is:
nomad
'wanderer' is the definition.
(I know that Nomad is a type of wanderer)
'turning on crazy' is the wordplay.
'turning' says the letters should be written in reverse.
'crazy' becomes 'mad' (synonyms).
'on' in reverse letter order 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" .)