"power of initiating," 1775, from French initiative (16c.), from Latin initiatus, past participle of initiare "to begin," from initium "a beginning" (see initial (adj.)). From 1793 as "disposition to take the lead." Phrase take the initiative recorded by 1815.
the initiative phase in the negotiations
initialism
initialize
initiand
initiate
initiation
initiative
initiatory
in-itselfness
inject
injection
injector