VAINGLORIOUS
big, swelled, vainglorious
(adjective) feeling self-importance; “too big for his britches”; “had a swelled head”; “he was swelled with pride”
Source: WordNet® 3.1
Etymology
Adjective
vainglorious (comparative more vainglorious, superlative most vainglorious)
With excessive vanity or unwarranted pride.
Source: Wiktionary
Vain`glo"ri*ous, a.
Definition: Feeling or indicating vainglory; elated by vanity; boastful.
"Arrogant and vainglorious expression." Sir M. Hale.
– Vain`glo"ri*ous*ly, adv.
– Vain`glo"ri*ous*ness, n.
Source: Webster’s Unabridged Dictionary 1913 Edition