sackcloth vs fabric

sackcloth and fabric both are nouns.

Word	Noun	Adjective	Verb	Adverb
sackcloth	Yes	No	No	No
fabric	Yes	No	No	No

As nouns, fabric is a hypernym of sackcloth; that is, fabric is a word with a broader meaning than sackcloth:

sackcloth: a coarse cloth resembling sacking
fabric: artifact made by weaving or felting or knitting or crocheting natural or synthetic fibers

Other hypernyms of sackcloth include cloth, material, textile.

sackcloth (noun)	fabric (noun)
a coarse cloth resembling sacking	artifact made by weaving or felting or knitting or crocheting natural or synthetic fibers
a garment made of coarse sacking; formerly worn as an indication of remorse	the underlying structure