imitate v.

c. 1400, "emulation; act of copying," from Old French imitacion, from Latin imitationem (nominative imitatio) "a copying, imitation," noun of action from past participle stem of imitari "to copy, portray, imitate," from PIE *im-eto-, from root *aim- "to copy." Meaning "an artificial likeness" is from c. 1600. As an adjective, from 1840.

Proto-Indo-European root meaning "to copy." 

It forms all or part of: emulate; emulation; emulous;  image; imaginary; imagination; imaginative; imagine; imago; imitable; imitate; imitative; imitator; inimitable.

It is the hypothetical source of/evidence for its existence is provided by: Latin imago "image," aemulus "emulous," imitari "to copy, portray, imitate;" Hittite himma- "imitation, substitute."

1580s, probably from imitate + -ive; or else from French imitatif, from Late Latin imitativus, from imitat-, stem of Latin imitari "to copy, portray" (from PIE root *aim- "to copy").