bosom friend

very close friend 知心朋友; 知己; 密友.

bore, boredom, boric, boring, born, born of, born-again, borne, boron, borough, borrow, borrower, borrowing, borrowings, Borstal, bortsch (also borsch), borzoi, bos'n, bosh, bosom, bosomy, boss, boss-eyed, boss-man, boss-shot, bossily, bossiness, bossy, botanical, botanist, botanize, -ise, botany, botch, botch (also botch-up), botcher, both, both...and, both...and..., bother, botheration,