fabrication vs untruth

fabrication and untruth both are nouns.

Word	Noun	Adjective	Verb	Adverb
fabrication	Yes	No	No	No
untruth	Yes	No	No	No

As nouns, untruth is a hypernym of fabrication; that is, untruth is a word with a broader meaning than fabrication:

Other hypernyms of fabrication include falsehood, falsity.

fabrication (noun)	untruth (noun)
the act of making something (a product) from raw materials	a false statement
the act of constructing something (as a piece of machinery)
writing in a fictional form
the deliberate act of deviating from the truth
a deliberately false or improbable account