hairsbreadth vs hair

hairsbreadth and hair both are nouns.

Word	Noun	Adjective	Verb	Adverb
hairsbreadth	Yes	No	No	No
hair	Yes	No	No	No

As nouns, hairsbreadth and hair are synonyms defined as:

Other synonyms of hairsbreadth include hair's-breadth, whisker.

hairsbreadth (noun)	hair (noun)
a very small distance or space	a filamentous projection or process on an organism
	cloth woven from horsehair or camelhair; used for upholstery or stiffening in garments
	a covering for the body (or parts of it) consisting of a dense growth of threadlike structures (as on the human head); helps to prevent heat loss
	any of the cylindrical filaments characteristically growing from the epidermis of a mammal
	filamentous hairlike growth on a plant
	a very small distance or space