Implement used in terrible daze (4)
I believe the answer is:
adze
'implement' is the definition.
(adze is a kind of implement)
'terrible daze' is the wordplay.
'terrible' indicates an anagram.
'daze' is an anagram of 'ADZE'.
'used in' is the link.
(Other definitions for adze that I've seen before include "Timber-shaping tool" , "One might cut" , "Tool, sounds like sums" , "Wood-dressing tool" , "One used to cut" .)