oiler vs worker

oiler and worker both are nouns.

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

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

oiler (noun)	worker (noun)
a cargo ship designed to carry crude oil in bulk	sterile member of a colony of social insects that forages for food and cares for the larvae
a well that yields or has yielded oil	a person who works at a specific occupation
a worker who oils engines or machinery	a member of the working class (not necessarily employed)
	a person who acts and gets things done