sit vs hunker down

sit and hunker down both are verbs.

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

As verbs, hunker down is a hyponym of sit; that is, hunker down is a word with a more specific, narrower meaning than sit:

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

Other hyponyms of sit include lounge, sprawl, perch, rest, roost, crouch, hunker, scrunch, scrunch up, squat.

sit (verb)	hunker down (verb)
serve in a specific professional capacity	hold stubbornly to a position
be in a position in which one's upper body is largely upright and supported by one's backside	sit on one's heels
show to a seat; assign a seat for	take shelter
take a seat
be in session
sit and travel on the back of animal, usually while controlling its motions
assume a posture as for artistic purposes
work or act as a baby-sitter
be around, often idly or without specific purpose
be located or situated somewhere