fee vs fee simple

fee and fee simple both are nouns.

Word	Noun	Adjective	Verb	Adverb
fee	Yes	No	Yes	No
fee simple	Yes	No	No	No

As nouns, fee simple is a hyponym of fee; that is, fee simple is a word with a more specific, narrower meaning than fee:

fee: an interest in land capable of being inherited
fee simple: a fee without limitation to any class of heirs; they can sell it or give it away

Other hyponyms of fee include fee tail.

fee (noun)	fee simple (noun)
a fixed charge for a privilege or for professional services	a fee without limitation to any class of heirs; they can sell it or give it away
an interest in land capable of being inherited

fee (verb)	fee simple (verb)
give a tip or gratuity to in return for a service, beyond the compensation agreed on