pong vs malodor

pong and malodor both are nouns.

Word	Noun	Adjective	Verb	Adverb
pong	Yes	No	No	No
malodor	Yes	No	No	No

As nouns, malodor is a hypernym of pong; that is, malodor is a word with a broader meaning than pong:

Other hypernyms of pong include fetor, foetor, malodour, mephitis, reek, stench, stink.

pong (noun)	malodor (noun)
an unpleasant smell	a distinctive odor that is offensively unpleasant