self-interest vs trait

self-interest and trait both are nouns.

Word	Noun	Adjective	Verb	Adverb
self-interest	Yes	No	No	No
trait	Yes	No	No	No

As nouns, trait is a hypernym of self-interest; that is, trait is a word with a broader meaning than self-interest:

self-interest (noun)	trait (noun)
concern for your own interests and welfare	a distinguishing feature of your personal nature
taking advantage of opportunities without regard for the consequences for others