draught vs downdraft

draught and downdraft both are nouns.

Word	Noun	Adjective	Verb	Adverb
draught	Yes	No	Yes	No
downdraft	Yes	No	No	No

As nouns, downdraft is a hyponym of draught; that is, downdraft is a word with a more specific, narrower meaning than draught:

draught: a current of air (usually coming into a chimney or room or vehicle)
downdraft: a strong downward air current

Other hyponyms of draught include updraft.

draught (noun)	downdraft (noun)
the act of moving a load by drawing or pulling	a strong downward air current
a large and hurried swallow
a dose of liquid medicine
the depth of a vessel's keel below the surface (especially when loaded)
a serving of drink (usually alcoholic) drawn from a keg
a current of air (usually coming into a chimney or room or vehicle)

draught (verb)	downdraft (verb)
make a blueprint of