Criticise one inside as a nuisance (4)
I believe the answer is:
pain
'a nuisance' is the definition.
(I know that nuisance can be written as pain)
'criticise one inside' is the wordplay.
'criticise' becomes 'pan' (informal term meaning to criticise heavily).
'one' becomes 'i' (Roman numeral).
'inside' is an insertion indicator.
'pan' going around 'i' is 'PAIN'.
'as' is the link.
(Other definitions for pain that I've seen before include "Agony" , "Suffering, ache" , "great discomfort" , "Suffering of body or mind" , "Unpleasant sensation" .)