Anticipating the usual time; applied to a periodical disease whose paroxysms return at an earlier hour at every repetition. / Previous; antecedent. / Of or pertaining to prolepsis; anticipative.

In a proleptic manner; anticipatorily.

Of a calendar, extrapolated to dates prior to its first adoption; of those used to adjust to or from the Julian calendar or Gregorian calendar. / Of an event, assigned a date that is too early.

(medicine) The art and science of predicting in medicine.