boon (n.) Look up boon at
late 12c., bone "petition," from Old Norse bon "a petition, prayer," from Proto-Germanic *boniz (source also of Old English ben "prayer, petition," bannan "to summon;" see ban).
boon (adj.) Look up boon at
in boon companion (1560s), only real survival of Middle English boon "good" (early 14c.), from Old French bon, from Latin bonus "good" (see bonus).