chador vs head covering

chador and head covering both are nouns.

Word	Noun	Adjective	Verb	Adverb
chador	Yes	No	No	No
head covering	Yes	No	No	No

As nouns, head covering is a hypernym of chador; that is, head covering is a word with a broader meaning than chador:

chador: a cloth used as a head covering (and veil and shawl) by Muslim and Hindu women
head covering: a garment that covers the head and face

Other hypernyms of chador include veil.

chador (noun)	head covering (noun)
a cloth used as a head covering (and veil and shawl) by Muslim and Hindu women	a garment that covers the head and face