fibril vs barb

fibril and barb both are nouns.

Word	Noun	Adjective	Verb	Adverb
fibril	Yes	No	No	No
barb	Yes	No	Yes	No

As nouns, barb is a hyponym of fibril; that is, barb is a word with a more specific, narrower meaning than fibril:

fibril: a very slender natural or synthetic fiber
barb: one of the parallel filaments projecting from the main shaft of a feather

Other hyponyms of fibril include cobweb, gossamer, chromatid, myofibril, myofibrilla, sarcostyle, rhizoid, hypha, paraphysis.

fibril (noun)	barb (noun)
a very slender natural or synthetic fiber	one of the parallel filaments projecting from the main shaft of a feather
	a subsidiary point facing opposite from the main point that makes an arrowhead or spear hard to remove
	the pointed part of barbed wire
	an aggressive remark directed at a person like a missile and intended to have a telling effect

fibril (verb)	barb (verb)
	provide with barbs