bumptious
The group of five young men wrote and sang bumptiously catchy songs.
It might be a difficult market, but this retailer is bumptiously boasting of record-breaking growth.
The central government did not like the emergence of a bumptiously self-governing region.

SMART Vocabulary: related words and phrases

Showing arrogance and conceit
(as) proud as Luciferidiom
airs and gracesidiom
arrogant
arrogantly
as if you owned the placeidiom
egoistically
egomaniacal
egomaniacally
egotistic
egotistically
patronizingly
pomposity
pompous
pompously
popinjay
swollen head
swollen-headed
talk down to someone
think the (whole) world revolves around youidiom
throw your weight aroundidiom