PRETERPLUPER'FECT, adjective [Latin proeter, beyond, plus, more, and perfectus, perfect.] Literally, beyond more than perfect; an epithet designating the tense of verbs which expresses action or being past prior to another past event or time; better denominated the prior past tense, that is, past prior to another event.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI