also live-long, of a period of time, "long, whole" c. 1400, lefe longe (day or night), from leve, lief "dear" (see lief), used here as an emotional intensive + long (adj.). From late 16c. conformed in spelling and pronunciation to live (v.) as lief grew strange. German has cognate die liebe lange (Nacht), etc., literally "the dear long (night)."