Canter around in a dream (6)
I believe the answer is:
trance
'dream' is the definition.
(I've seen this in other clues)
'canter around' is the wordplay.
'around' indicates anagramming the letters.
'canter' is an anagram of 'TRANCE'.
'in a' acts as a link.
(Other definitions for trance that I've seen before include "state of mind" , "Deep sleeplike state" , "Canter into suspended animation" , "Reverie" , "Dream-like state" .)