Large plugs seen and disregarded (8)
I believe the answer is:
slighted
'disregarded' is the definition.
('slight' can be a synonym of 'disregard')
'large plugs seen' is the wordplay.
'large' becomes 'l'.
'plugs' means one lot of letters goes inside another (plug can mean to fill a gap).
'seen' becomes 'sighted' (I've seen this before).
'l' placed into 'sighted' is 'SLIGHTED'.
'and' acts as a link.
(Other definitions for slighted that I've seen before include "Offended" , "put down" , "Gave the cold shoulder to" , "Insulted with delights" .)