Ant. Infrequently, seldom, rarely.
Old. Aged, ancient, primitive, pristine, antique, antiquated, old-fashioned, obsolete; senile; gray, hoary, olden, immemorial, time-honored, decrepit, elderly, patriarchal, remote, venerable, time-worn.
Ant. Youthful, childlike, young; recent, modern, fresh, new-fashioned, current.
Omen. Prognostic, augury, presage, sign, portent, foreboding.
Ant. Fulfilment, event, occurrence, realization.
Ominous. Significant, portentous, unpropitious, threatening, inauspicious, foreboding, premonitory, suggestive.
Ant. Encouraging, auspicious, propitious.
Omit, v. Leave out, neglect, forbear, fail, miss, overlook.
Ant. Consider, observe, notice, attend, regard.
Omnipotent. All-powerful, irresistible, Almighty.