oil well vs wildcat

oil well and wildcat both are nouns.

Word	Noun	Adjective	Verb	Adverb
oil well	Yes	No	No	No
wildcat	Yes	Yes	No	No

As nouns, wildcat is a hyponym of oil well; that is, wildcat is a word with a more specific, narrower meaning than oil well:

oil well: a well that yields or has yielded oil
wildcat: an exploratory oil well drilled in land not known to be an oil field

Other hyponyms of oil well include gusher, spouter, stripper, stripper well, wildcat well.

oil well (noun)	wildcat (noun)
a well that yields or has yielded oil	any small or medium-sized cat resembling the domestic cat and living in the wild
	an exploratory oil well drilled in land not known to be an oil field
	a cruelly rapacious person

oil well (adjective)	wildcat (adjective)
	(of a mine or oil well) drilled speculatively in an area not known to be productive
	without official authorization
	outside the bounds of legitimate or ethical business practices