fill vs stuff

fill and stuff both are nouns.

Word	Noun	Adjective	Verb	Adverb
fill	Yes	No	Yes	No
stuff	Yes	No	Yes	No

As nouns, stuff is a hypernym of fill; that is, stuff is a word with a broader meaning than fill:

fill: any material that fills a space or container
stuff: the tangible substance that goes into the makeup of a physical object

Other hypernyms of fill include material.

As verbs, stuff is a hyponym of fill; that is, stuff is a word with a more specific, narrower meaning than fill:

fill (noun)	stuff (noun)
a quantity sufficient to satisfy	miscellaneous unspecified objects
any material that fills a space or container	unspecified qualities required to do or be something
	a critically important or characteristic component
	senseless talk
	information in some unspecified form
	informal terms for personal possessions
	the tangible substance that goes into the makeup of a physical object

fill (verb)	stuff (verb)
become full	fill with a stuffing while cooking
make full, also in a metaphorical sense	fill tightly with a material
plug with a substance	treat with grease, fill, and prepare for mounting
fill to satisfaction	overeat or eat immodestly; make a pig of oneself
eat until one is sated	cram into a cavity
fill, satisfy or meet a want or need or condition or restriction	obstruct
assume, as of positions or roles	press or force
appoint someone to (a position or a job)
occupy the whole of