everlast

Back-formation from everlasting, equivalent to ever +‎ last.

everlast (third-person singular simple present everlasts, present participle everlasting, simple past and past participle everlasted)

1. (intransitive, rare) To last always or forever; continue; endure; remain.
   • 2009, Frank Seinsheimer, Poetical Commentary:

     [...] as he flew through the air / to smother the blast / he reached a state of grace / that will everlast [...]

   • 2010, Sharyn Munro, The Woman on the Mountain:

     They had survived several fires in their twenty years and probably would have everlasted but this had been exceptional.

• everlastable

• AVL trees