tibia vara vs impairment

tibia vara and impairment both are nouns.

Word	Noun	Adjective	Verb	Adverb
tibia vara	Yes	No	No	No
impairment	Yes	No	No	No

As nouns, impairment is a hypernym of tibia vara; that is, impairment is a word with a broader meaning than tibia vara:

tibia vara: a leg bowed outward at the knee (or below the knee)
impairment: the condition of being unable to perform as a consequence of physical or mental unfitness

Other hypernyms of tibia vara include leg, disability, disablement, handicap.

tibia vara (noun)	impairment (noun)
a leg bowed outward at the knee (or below the knee)	damage that results in a reduction of strength or quality
	the act of making something futile and useless (as by routine)
	the occurrence of a change for the worse
	the condition of being unable to perform as a consequence of physical or mental unfitness
	a symptom of reduced quality or strength