hunker vs sit down

hunker and sit down both are verbs.

Word	Noun	Adjective	Verb	Adverb
hunker	No	No	Yes	No
sit down	No	No	Yes	No

As verbs, sit down is a hypernym of hunker; that is, sit down is a word with a broader meaning than hunker:

hunker: sit on one's heels
sit down: be in a position in which one's upper body is largely upright and supported by one's backside

Other hypernyms of hunker include sit.

hunker (verb)	sit down (verb)
sit on one's heels	show to a seat; assign a seat for
	be in a position in which one's upper body is largely upright and supported by one's backside
	take a seat