Groove found, in truth (3)
I believe the answer is:
rut
'groove' is the definition.
(synonyms)
'in truth' is the wordplay.
'in' says the answer is hidden in the clue.
'RUT' can be found hidden inside 'truth'.
'found' is the link.
(Other definitions for rut that I've seen before include "Groove or routine" , "Deep vehicle track" , "Monotony that's hard to escape" , "Boring groove to be stuck in!" , "Groove or furrow - don't get into one" .)