primate vs monkey

primate and monkey both are nouns.

Word	Noun	Adjective	Verb	Adverb
primate	Yes	No	No	No
monkey	Yes	No	Yes	No

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

primate: any placental mammal of the order Primates; has good eyesight and flexible hands and feet
monkey: any of various long-tailed primates (excluding the prosimians)

Other hyponyms of primate include simian, ape, anthropoid, hominoid, hominid, prosimian, lemur, tarsier.

primate (noun)	monkey (noun)
any placental mammal of the order Primates; has good eyesight and flexible hands and feet	any of various long-tailed primates (excluding the prosimians)
a senior clergyman and dignitary	one who is playfully mischievous

primate (verb)	monkey (verb)
	do random, unplanned work or activities or spend time idly
	play around with or alter or falsify, usually secretively or dishonestly