Immediately. Presently, this instant, straightway, directly, forthwith, at once, now, right off, instantly, without delay.
Ant. Hereafter, by-and-by, after a while, sometime.
Immemorial. Olden, ancient, hoary, archaic, primitive, remote, time-honored, primordial.
Ant. Recent, modern, late, fresh, upstart.
Immerse. Dip, plunge, submerge, sink, douse, duck, bury; soak, steep, macerate, drown, inundate, overwhelm.
Ant. Dry, drain, parch, ventilate, air, ground, strand.
Immigration. Migration, colonization, settlement.
Ant. Exodus, emigration.
Imminent. Impending, hovering, threatening.
Ant. Improbable, doubtful, unexpected, unlikely, contingent, chimerical, problematical; warded, staved, escaped.