| blighty | n. | (often capitalized) England; wound necessitating soldier’s removal from the front to the homeland | slang | |
| blim | n. | small piece of hashish | slang | |
| blind baggage | n. | railway postal car with no door on the end, usu. just behind the tender; riding the rails unseen by trainyard bulls | ||
| blinkard | n. | person with poor vision; idjut | obsolete | |
| blirt | v. | to burst into tears | ||
| blithe | adj. | heedless; jocund, merry | ||
| blowzy | adj. | ruddy, rude, and dirty | ||
| blucher | n. | leather half-boot, strong high shoe | ||
| bludge | v. | to shirk; to scrounge; to live off another’s earnings, esp. as a pimp | slang | |
| blue | v. | to squander, to spend wastefully or without restraint | slang | |
| bob-a-job | n. | children performing light household work for a nominal fee | British | |
| bodge | v. | to patch poorly or clumsily | ||
| bodkin | n. | large thick needle for piercing leather or cloth; dagger | ||
| bog standard | adj. | just ordinary (with derogatory connotation) | informal | |
| boggart | n. | malevolent household fairy in English folklore, frequently stealing small items and souring milk | ||
| bole | n. | tree trunk | ||
| bolshie | n. | Bolshevik, communist; leftist | slang | |
| bolt | v. | to change rapidly from growing primarily leaves to produce instead seeds and flowers | botany | |
| bolus | n. | overlarge pill; round soft mass, esp. of chewed food | ||
| bombazeen | n. | (var. of bombasine) twill fabric of worsted and (often) silk or cotton, used as mourning garb when dyed black | ||
| bombinate | v. | to buzz, to hum | ||
| bonhomous | adj. | cheerful, full of bonhomie | ||
| bonze | n. | Buddhist monk, particularly of Japan, so-called by Europeans | ||
| boor | n. | rude person; yokel; peasant | ||
| boot | v. | to improve; to profit, to avail | ||
| bootjack | n. | forked device designed to assist in removal of riding boots | ||
| bootless | adj. | useless, ineffectual, without effect or gain | archaic | |
| borage | n. | herbaceous plant with blue flowers, thought to have medicinal properties | ||
| borborygmus | n. | stomach noise made by internal gas movement; wamble | ||
| bord | n. | coalface leading into the seam; roadway in mine through which coal is extracted | ||
| bore | n. | large tidal wave caused either by meeting of two tides or by tidal water rushing into a narrow estuary | ||
| boreal | adj. | of the north, of the north wind | ||
| borstal | n. | reformatory school for juvenile delinquents | ||
| bort | n. | low-grade diamonds and fragments of good diamonds, used commonly as abrasive | ||
| boscage | n. | mass of shrubs or trees, thicket | ||
| bosk | n. | thicket of bushes | ||
| bosky | adj. | of or related to bushes or shrubs; bushy, covered or shielded by low foliage; shady | ||
| bothy | n. | small cottage or hut, usu. of only a single room | ||
| bottomry | n. | shipping contract wherein the vessel is used as collateral to raise money financing a commercial voyage | nautical | |
| bougie | n. | thin flexible instrument for insertion or dilation of bodily passages | ||
| bourne | n. | boundary, limit; goal | ||
| bouser | n. | tippler, heavy drinker, boozer | obsolete | |
| boustrophedon | adv. | moving alternately from right to left and from left to right, as in certain ancient texts and inscriptions | ||
| bowse | v. | to haul with tackle [also bouse] | nautical | |
| boxty | n. | Irish potato pancake or bread | ||
| brach | n. | female hound; disgusting woman | archaic | |
| bract | n. | small specialized leaf growing with a plant’s flower | botany | |
| bradawl | n. | small hand-boring tool | ||
| bradykinin | n. | peptide hormone that mediates inflammation | ||
| braggadocio | n. | boastful speech, empty bragging |
