gusher vs oiler

gusher and oiler both are nouns.

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

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

gusher: an oil well with a strong natural flow so that pumping is not necessary
oiler: a well that yields or has yielded oil

Other hypernyms of gusher include oil well.

gusher (noun)	oiler (noun)
an oil well with a strong natural flow so that pumping is not necessary	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