Irrepeatable

Part of speech: adjective

Definitions

1. Incapable of being repeated or done again; describing an event or action that is unique and cannot recur; signifying an occurrence limited to a single instance
2. Characterizing something that cannot be duplicated or replicated; referring to a moment or experience that happens only once and cannot be reproduced; indicating an outcome or result that is singular and not reproducible
3. Denoting an act or situation that is one-time only and irreversible; illustrating a phenomenon that cannot be repeated or imitated; relating to a circumstance that exists just once and is not repeatable

Etymology: "Irrepeatable" is a plain formation: the prefix "ir-" (a form of "in-", meaning "not") attached to "repeatable", which itself comes from "repeat" plus the suffix "-able". The prefix takes the form "ir-" before a root beginning with "r", the same assimilation seen in "irregular" and "irreversible," so the word is built from parts English already had in abundance. The base, "repeatable," describes something that can be done or occurred again. Adding "ir-" flips it to mean that something cannot be repeated, and in practice the word is used for moments, events, and experiences that happen only once and cannot be recreated. Its meaning is therefore essentially the negation of an existing adjective rather than a new idea.