self-seeker vs hustler

self-seeker and hustler both are nouns.

Word	Noun	Adjective	Verb	Adverb
self-seeker	Yes	No	No	No
hustler	Yes	No	No	No

As nouns, hustler is a hyponym of self-seeker; that is, hustler is a word with a more specific, narrower meaning than self-seeker:

self-seeker: a person who places expediency above principle
hustler: a shrewd or unscrupulous person who knows how to circumvent difficulties

Other hyponyms of self-seeker include backscratcher, bottom feeder, carpetbagger, operator, wheeler dealer, timeserver.

self-seeker (noun)	hustler (noun)
a person who places expediency above principle	a shrewd or unscrupulous person who knows how to circumvent difficulties
	a prostitute who attracts customers by walking the streets