supertanker vs oiler

supertanker and oiler both are nouns.

Word	Noun	Adjective	Verb	Adverb
supertanker	Yes	No	No	No
oiler	Yes	No	No	No

As nouns, oiler is a hypernym of supertanker; that is, oiler is a word with a broader meaning than supertanker:

Other hypernyms of supertanker include oil tanker, tank ship, tanker.

supertanker (noun)	oiler (noun)
the largest class of oil tankers	a cargo ship designed to carry crude oil in bulk
	a well that yields or has yielded oil
	a worker who oils engines or machinery