Nice without trainee rustic (7)
I believe the answer is:
'rustic' is the definition.
(I know that peasant is a type of rustic)
'nice without trainee' is the wordplay.
'nice' becomes 'pleasant' (similar in meaning).
'without' indicates named letters should be taken away.
'trainee' becomes 'l'.
'pleasant' with 'l' removed is 'PEASANT'.
(Other definitions for peasant that I've seen before include "Yokel" , "Bumpkin" , "Lowly tiller of land" , "Rural labourer" , "Agricultural labourer of low status" .)