THESAURUS
Once
alone, already, ancient, anytime, anyway, anywise, apart, at a stroke, at all, at any time, at intervals, at once, at one time, at times, at whatever time, before, by itself, bygone, conclusively, decidedly, definitely, directly, earlier, early, erstwhile, finally, for good, fore, former, formerly, heretofore, if ever, immediately, immemorial, in a jiffy, in a trice, in a wink, in the singular, individually, instantly, just this once, late, long ago, no matter when, now and again, occasionally, old, olden, on one occasion, once for all, one by one, one day, one fine morning, one time, onetime, only once, particularly, past, per se, periodically, positively, prehistoric, previous, previously, primeval, primitive, prior, promptly, quondam, recent, right away, separately, severally, simultaneously, single-handedly, singly, singularly, some time ago, sometime, sometimes, sporadically, then, time was, together, whenever, whensoever, whilom, without delay
ROGET THESAURUS
Once
Time
N
time, duration, period, term, stage, space, span, spell, season, the whole time, the whole period, space-time, course, snap, intermediate time, while, interim, interval, pendency, intervention, intermission, intermittence, interregnum, interlude, respite, era, epoch, time of life, age, year, date, decade, moment, glass of time, sands of time, march of time, Father Time, ravages of time, arrow of time, river of time, whirligig of time, noiseless foot of time, scythe, continuing, on foot, permanent, while, whilst, during, pending, during the time, during the interval, in the course of, at that point, at that point in time, for the time being, day by day, in the time of, when, meantime, meanwhile, in the meantime, in the interim, ad interim, pendente lite, de die in diem, from day to day, from hour to hour, hourly, always, for a time, for a season, till, until, up to, yet, as far as, by that time, so far, hereunto, heretofore, prior to this, up to this point, the whole time, all the time, all along, throughout, for good, hereupon, thereupon, whereupon, then, anno Domini, A, D, ante Christum, A, C, before Christ, B, C, anno urbis conditae, A, U, C, anno regni, A, R, once upon a time, one fine morning, one fine day, one day, once, time flies, tempus fugit, time runs out, time runs against, race against time, racing the clock, time marches on, time is of the essence, time and tide wait for no man, ad calendas Groecas, panting Time toileth after him in vain, 'gainst the tooth of time and razure of oblivion, rich with the spoils of time, tempus edax rerum, the long hours come and go, the time is out of joint, Time rolls his ceaseless course, Time the foe of man's dominion, time wasted is existence, used is life, truditur dies die, volat hora per orbem, carpe diem.
The Past
N
the past, past time, days of yore, times of yore, days of old, times of old, days past, times past, days gone by, times gone by, bygone days, old times, ancient times, former times, fore time, the good old days, the olden time, good old time, auld lang syne, eld, antiquity, antiqueness, status quo, time immemorial, distance of time, remote age, remote time, remote past, rust of antiquity, paleontology, paleography, paleology, paleozoology, palaetiology, archaeology, paleogeography, paleoecology, paleobotany, paleoclimatoogy, archaism, antiquarianism, medievalism, Pre-Raphaelitism, paleography, retrospect, retrospection, looking back, memory, laudator temporis acti, medievalist, Pre-Raphaelite, antiquary, antiquarian, archmologist, Oldbuck, Dryasdust, ancestry, past, gone, gone by, over, passed away, bygone, foregone, elapsed, lapsed, preterlapsed, expired, no more, run out, blown over, has-been, that has been, extinct, antediluvian, antebellum, never to return, gone with the wind, exploded, forgotten, irrecoverable, obsolete, former, pristine, quondam, ci-devant, late, ancestral, foregoing, last, latter, recent, over night, preterperfect, preterpluperfect, looking back, retrospective, retroactive, archaeological, paleo-, archaeo-, formerly, of old, of yore, erst, whilom, erewhile, time was, ago, over, in the olden time, anciently, long ago, long since, a long while, a long time ago, years ago, yesteryear, ages ago, some time ago, some time since, some time back, yesterday, the day before yesterday, last year, ultimo, lately, retrospectively, ere now, before now, till now, hitherto, heretofore, no longer, once, once upon a time, from time immemorial, from prehistoric times, in the memory of man, time out of mind, already, yet, up to this time, ex post facto, time was, the time has been, the time hath been, you can't go home again, fuimus Troes, fruit Ilium, hoc erat in more majorum, O call back yesterday, bid time return, tempi passati, the eternal landscape of the past, ultimus Romanorum, what's past is prologue, whose yesterdays look backward with a smile, Time with reference to a particular period.
Infrequency
N
infrequency, rareness, rarity, fewness, seldomness, uncommonness, unfrequent, infrequent, rare, rare as a blue diamond, few, scarce, almost unheard of, unprecedented, which has not occurred within the memory of the ol, not within one's previous experience, not since Adam, scarce as hen's teeth, one in a million, few and far between, seldom, rarely, scarcely, hardly, not often, not much, infrequently, unfrequently, unoften, scarcely, scarcely ever, hardly ever, once in a blue moon, once, once in a blue moon, once in a million years, once for all, once in a way, pro hac vice, ein mal kein mal.