adj

• Lasting or enduring forever; endless, eternal.
• (chiefly hyperbolic, informal)
  "this everlasting nonsense"
• (chiefly hyperbolic, informal)
  "It is never dark here, you are novv come to the Country of Everlaſting Day; VVhat think you? Is not this Eliſium?"
• (chiefly hyperbolic, informal)
  "Adr[iana]. VVhere is thy Maſter Dromio? Is he vvell? / S. Dro. [Dromio of Syracuse] No, he's in Tartar limbo, vvorſe than hell: / A diuell in an euerlaſting garment hath him; / On vvhoſe hard heart is button'd vp vvith ſteele: / A Feind, a Fairie, pittileſſe and ruffe: / A VVolfe, nay vvorſe, a fellovv all in buffe: […]"

adv

• Synonym of everlastingly.
  "[…] Miranda’s impression, conveyed in privacy to Jane, was that Hannah was close as the bark of a tree, and consid’able selfish too; that when she’d clim’ as fur as she could in the world, she’d kick the ladder out from under her, everlastin’ quick; […]"
• Synonym of everlastingly.
  "You your ſelves in the opinion of this everlaſting talkative Advocate of the King, your accuſer, vvent more than half-vvay tovvards it; […]"

noun

• (countable, botany) Chiefly with a descriptive word: short for everlasting flower (“any of several plants, chiefly of the family Asteraceae (principally the tribe Gnaphalieae), having flowers that retain their colour and form when dried; also, a flower of such a plant”)
  "This yellovv Euerlaſting or Floure-Gentle, called of the later Herbariſts Yellovv Strœcas, is a plant that hath ſtalkes of a ſpan long, […] The floures ſtand on the tops of the ſtalks, […] of a bright yellovv colour; vvhich being gathered before they be ripe, do keep their colour and beauty a long time vvithout vvithering, […]"
• (countable, archaic) Preceded by the: someone or something that lasts forever, or that that has always existed and will continue to exist forever; an eternal, an immortal; specifically (Christianity), God.
  "[T]he people of Thebais in Ægipt, reiected all the ſaid abſurdities of many Goddes, ſaying that there was none other God but only he whom they called Cnef [Kneph?], which was neuer borne, nor could euer dye, that is to ſay the Euerlaſting."
• (clothing, footwear, historical)
  "There is a young man, a third-rate coxcomb, whose first care is always to flourish a white handkerchief, and brush the seat of a tight pair of black silk pantaloons, which shine as if varnished. They must have been made of the stuff called ‘everlasting,’ or perhaps of the same piece as Christian’s garments, in the Pilgrim’s Progress, for he put them on two summers ago, and has not yet worn the gloss off."
• (clothing, footwear, historical)