egotism vs swelled head

egotism and swelled head both are nouns.

Word	Noun	Adjective	Verb	Adverb
egotism	Yes	No	No	No
swelled head	Yes	No	No	No

As nouns, egotism and swelled head are synonyms defined as:

Other synonyms of egotism include self-importance.

egotism (noun)	swelled head (noun)
an exaggerated opinion of your own importance	an exaggerated opinion of your own importance
an inflated feeling of pride in your superiority to others