Plugging great work, notice swagger (7)
I believe the answer is:
bravado
'swagger' is the definition.
(I've seen this in another clue)
'plugging great work notice' is the wordplay.
'plugging' means one lot of letters goes inside another (inserted letters plug up a gap in the word).
'great work' becomes 'bravo' ('bravo' means 'well done' or 'good work').
'notice' becomes 'ad' (short for advert).
'bravo' placed around 'ad' is 'BRAVADO'.
(Other definitions for bravado that I've seen before include "Bottle" , "Boastfulness" , "showing off" , "Swaggering confidence" , "Swag" .)