inattentive, adj. 1. heedless, unmindful, neglectful, unheeding, careless, inconsiderate, negligent, remiss; unobservant, unwatchful, unaware, undiscerning.
2. wandering, daydreaming, musing, vague, dreamy, listless, supine, drowsy, sleepy, nodding, oscitant; abstracted, preoccupied, engrossed or lost in thought or reverie, rapt, lost, absent, deaf, blind, staring into space; off in a world of one's own, with one's head in the clouds, in the clouds, a million miles away; oblivious, detached, distracted, faraway, off guard, caught napping, absent-minded, forgetful; in a brown study, in a blue funk, indifferent, apathetic.
inaudible, adj. imperceptible, out of earshot or hearing, impossible to hear, not heard; indistinct, faint, muted, soft, gentle, quiet, dull, low; muffled, stifled, unclear, hard to hear, hard to make out; whispered, muttered, mumbled, murmured; mute, still, silent, noiseless.
inaugurate, v. 1. initiate, begin, start, commence, Inf kick off; break ground, ring up the curtain on, get the show on the road, get underway; launch, Inf. get off the ground, start off, forward; set out on, start out, enter into, take the first step; get going, set sail, hit the road or trail, be off.
2. induct, install, instate, Rare, auspicate; introduce, bring in, lead in, usher in, inaugurate, invest, chair, establish; crown, enthrone; frock, Eccles. ordain, consecrate.
inauguration, n. 1. initiation, beginning, outset, start, commencement, Inf. kickoff; breaking ground, getting underway.
2. induction, installation, instatement; introduction, bringing in, ushering in; inauguration, investiture, chairing, establishment; coronation, crowning, enthronement; frocking, Eccles. ordination, Eccles. or-dainment, consecration.
inauspicious, adj. unpropitious, unpromising, hostile, dark, gloomy, threatening, lowering; unfortunate, unlucky, infelicitous, untoward, untimely, unhappy; ominous, ill-boding, portentous, sinister, menacing, of bad omen, ill-starred, ill-omened, ill-fated, doomed.
inborn, adj. innate, inherent, Archaic, ingenerate, native; inbred, congenital, connate, connatural, natural; organic, constitutional, structural; inherited, hereditary, in the blood, in the family, in the genes.
incalculable, adj. 1. measureless, immeasurable, fathomless, unfathomable; inestimable, incomputable, uncountable, not to be reckoned; innumerable, countless, untold, uncounted, numberless, sumless, without number; unmeasured, indeterminate, undetermined; endless, infinite, inexhaustible, no end of, without end, bottomless; multitudinous, very great, enormous, immense, vast.
2. unpredictable, undeterminable, unforeseeable, un-divinable; chance, fortuitous, adventitious, accidental, haphazard; Inf. fluky, Inf. dicey, Inf. chancy, coincidental, epiphenomenal, noncausal, casual.
3. uncertain, unsure, unaccountable, unmotivated; unexplainable, inexplicable, puzzling, enigmatic, paradoxical.
incandescence, n. phosphorescence, fluorescence, illumination, irradiation, tribophosphorescence; nitidity, luminescence, luminosity, triboluminescence; sheen, glow, splendor, luster; brilliance, brightness, effulgence, radiance, iridescence, resplendence, refulgence, Archaic, fulgor; shine, fire, flame, blaze; flash, fulguration, beam, ray; twinkle, twinkling, sparkle, sparkling; coruscation, scintillation, glistening, shimmer, glint, glance; gleam, glitter, glimmer, flicker, Archaic. glister.