envy vs covet

envy is a noun but covet is not a noun.

Word	Noun	Adjective	Verb	Adverb
envy	Yes	No	Yes	No
covet	No	No	Yes	No

As verbs, covet is a hyponym of envy; that is, covet is a word with a more specific, narrower meaning than envy:

envy: be envious of; set one's heart on
covet: wish, long, or crave for (something, especially the property of another person)

envy (noun)	covet (noun)
spite and resentment at seeing the success of another (personified as one of the deadly sins)
a feeling of grudging admiration and desire to have something that is possessed by another

envy (verb)	covet (verb)
be envious of; set one's heart on	wish, long, or crave for (something, especially the property of another person)
feel envious towards; admire enviously