一緒【いっしょ】
together, at the same time, same, identical
一番【いちばん】
number one, first, first place, best, most, game, round, bout, as a test, as an experiment, by way of experiment, by way of trial, tentatively, song (e.g. in noh), piece
一体【いったい】
(what) the heck, (why) in the world, (who) on earth, one object, one body, unity, one form, one style, one Buddhist image (or carving, etc.), generally, in general
一同【いちどう】
all present, all concerned, all of us
一緒に【いっしょに】
together (with), at the same time, in a lump
一生【いっしょう】
whole life, a lifetime, all through life, one existence, a generation, an age, the whole world, the era, (the only, the greatest, etc.) of one's life
唯一【ゆいいつ】
only, sole, unique
一部【いちぶ】
one part, one portion, one section, some, one copy (e.g. of a document)
もう一度【もういちど】
once more, again
一方【いっぽう】
one (esp. of two), the other, one way, the other way, one direction, the other direction, one side, the other side, one party, the other party, on the one hand, on the other hand, whereas, although, but at the same time, meanwhile, in turn, just keeps, being inclined to ..., tending to be ..., tending to do ..., continuously ..., just keeps on ...ing, only
一瞬【いっしゅん】
instant, moment, for an instant
一つ【ひとつ】
one, for one thing, only, (not) even, just (e.g. "just try it"), some kind of, one type of
一番【ひとつがい】
pair, couple, brace
一応【いちおう】
more or less, though not quite satisfactorily, after a fashion, pretty much, roughly, so far as it goes, tentatively, for the time being, just in case, once
一切【いっさい】
all, everything, entirety, the whole, absolutely (not), (not) at all, (none) whatsoever, without exception
一度【いちど】
once, one time, on one occasion, temporarily, for a moment, one degree, one tone, one musical interval
一家【いっか】
a family, a household, a home, one's family, whole family, (one's own) style, school, gang, (yakuza) family
一生懸命【いっしょうけんめい】
very hard, with utmost effort, as hard as one can, with all one's might, for dear life, eagerly, desperately
一気に【いっきに】
in one go, in one gulp, in one breath, without stopping, without pausing, without a rest, in one sitting, at a stretch, suddenly, all of a sudden, all at once
一方【ひとかた】
one person, ordinary, common