In truth, it's monotonous (3)
I believe the answer is:
rut
'in truth it's monotonous' is the definition.
I can't tell whether this defines the answer.
'in truth it's monotonous' is the wordplay.
'in' says the answer is hidden in the clue.
'RUT' is hidden in the letters of 'truth monotonous'.
Can you help me to learn more?
(Other definitions for rut that I've seen before include "hazard in the road" , "Settled routine" , "Furrow - dreary routine" , "Dull routine behaviour" , "Road depression, difficult to get out of" .)