Wandered off (7)
I believe the answer is:
strayed
'wandered off' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for strayed that I've seen before include "Went off the track" , "Went off course" , "Wandered; digressed" , "Went wrong" , "Erred, wandered" .)