Perpetual means going on and on with no stop in sight. The perpetual hum of the fridge at three in the morning; the perpetual roadworks on the same stretch of ring road, year after year.
It works two ways. One is literal, and it belongs to law and science: a perpetual lease has no end date, perpetual snow never melts, and a perpetual motion machine is the impossible engine that would run for ever. The other is the everyday complaint — his perpetual moaning, her perpetual lateness — where perpetual means constant and wearing on the nerves. The formal partner is in perpetuity, the phrase contracts use for rights that never run out. Perpetual sits higher in tone than never-ending: you write it in a will and say never-ending to a friend.
1adjectiveperpetualNever ending; continuing for all time.
“The mountain wears a cap of perpetual snow.”
synonyms: endless, everlasting, eternal
2adjectiveconstantHappening again and again, with no break.
“I am tired of his perpetual complaining.”
3adjectivevalidValid or held for all time, with no end date.
“The family was granted a perpetual right of way across the field.”
Too few real examples of this word to estimate which sense is commonest.
Also accepted in games: eternal, constant
English took perpetual through Old French perpetuel from Latin perpetuālis, recorded with the sense universal, built on perpetuus and traced back to the verb petō. The thread underneath is of something that carries straight on through, all the way, without a pause. The same Latin gives in perpetuity, which lawyers still write when they mean for ever.
Proto-Indo-European
*peth₂-
Latin
perpetuālis — universal
Old French
perpetuel
Middle English
perpetuel
English, today
perpetual
From Middle English perpetuel, from Old French perpetuel, from Latin perpetuālis (“universal”), from perpetuus, from petō.
Etymology from Wiktionary, CC BY-SA