Wander in terror (3)
I believe the answer is:
err
'wander' is the definition.
(thesaurus)
'in terror' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ERR' is hidden within 'terror'.
(Other definitions for err that I've seen before include "Be incorrect" , "Miscalculate" , "Make mistakes" , "Miss the mark" , "Bungle" .)