Rustic in Nice left out (7)
I believe the answer is:
peasant
'rustic' is the definition.
(I know that peasant is a type of rustic)
'nice left out' is the wordplay.
'nice' becomes 'pleasant' (associated in meaning).
'left' becomes 'l' (common abbreviation).
'out' is a deletion indicator.
'pleasant' with 'l' removed is 'PEASANT'.
'in' is the link.
(Other definitions for peasant that I've seen before include "rude fellow" , "Poor farmworker" , "Poor agricultural worker" , "Revolting person" , "Poor worker on the land" .)