I. ˈbün noun
Etymology: Middle English bone prayer, request, the favor requested, from Old Norse bōn request; akin to Old English bēn prayer, bannan to summon — more at ban
Date: 12th century
1. : benefit , favor ; especially : one that is given in answer to a request
2. : a timely benefit : blessing
II. adjective
Etymology: Middle English bon, from Anglo-French, good — more at bounty
Date: 14th century
1. archaic : favorable
2. : convivial
a boon companion