pillar vs protagonist

pillar and protagonist both are nouns.

Word	Noun	Adjective	Verb	Adverb
pillar	Yes	No	No	No
protagonist	Yes	No	No	No

As nouns, protagonist is a hypernym of pillar; that is, protagonist is a word with a broader meaning than pillar:

Other hypernyms of pillar include admirer, booster, champion, friend, supporter.

pillar (noun)	protagonist (noun)
(architecture) a tall vertical cylindrical structure standing upright and used to support a structure	a person who backs a politician or a team etc.
a vertical cylindrical structure standing alone and not supporting anything (such as a monument)	the principal character in a work of fiction
a fundamental principle or practice
a prominent supporter
anything that approximates the shape of a column or tower