"recently or just begun," 1530s, from Latin inchoatus, past participle of inchoare, alteration of incohare "commence, begin," probably originally "to hitch up," traditionally derived from in- "in" (from PIE root *en "in") + a verb from cohum "strap (fastened to the oxen's yoke)," a word of obscure origin. De Vaan says that as, incohere "is a frequent verb, ... its meaning can easily have derived from 'to yoke a plough to a team of oxen' ..., in other words, 'to start work.' Thus, there might be a core of truth in the ancient connection of cohum with a yoke."
word-forming element making adjectives from verbs, meaning "pertaining to, tending to; doing, serving to do," in some cases from Old French -if, but usually directly from Latin adjectival suffix -ivus (source also of Italian and Spanish -ivo). In some words borrowed from French at an early date it has been reduced to -y (as in hasty, tardy).
1650s, "denoting the initial point or step," from French inceptif (16c.), from Latin incept-, past participle stem of incipere "to begin" (see inception). Interchangeable with inchoative. As a noun, "an inceptive verb," from 1610s.
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Definitions of inchoative from WordNet
aspect with regard to the beginning of the action of the verb;