1 [buhm]
a person who avoids work and sponges on others; loafer; idler.
a tramp, hobo, or derelict.
Informal. an enthusiast of a specific sport or recreational activity, especially one who gives it priority over work, family life, etc.: a ski bum; a tennis bum.
Informal. an incompetent person.
a drunken orgy; debauch.
verb (used with object), bummed, bumming.
Informal. to borrow without expectation of returning; get for nothing; cadge: He's always bumming cigarettes from me.
Slang. to ruin or spoil: The weather bummed our whole weekend.
verb (used without object), bummed, bumming.
to sponge on others for a living; lead an idle or dissolute life.
to live as a hobo.
adjective, bummer, bummest. Slang.
of poor, wretched, or miserable quality; worthless.
disappointing; unpleasant.
erroneous or ill-advised; misleading: That tip on the stock market was a bum steer.
lame: a bum leg.
Verb phrases
bum around, Informal. to travel, wander, or spend one's time aimlessly: We bummed around for a couple of hours after work.
bum (someone) out, Slang. to disappoint, upset, or annoy: It really bummed me out that she could have helped and didn't.
on the bum, Informal.
living or traveling as or in a manner suggesting that of a hobo or tramp.
in a state of disrepair or disorder: The oven is on the bum again.

1860–65, Americanism; perhaps shortening of or back formation from bummer1; adj. senses of unclear relation to sense “loafer” and perhaps of distinct orig.

2. vagabond, vagrant.
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2 [buhm]
noun Chiefly British Slang.
the buttocks; rump.

1350–1400; Middle English bom; of uncertain origin


3 [buhm]
noun Military Slang.
a reproduction of a document made with copying equipment.
a bag into which classified waste is put in preparation for destruction.

perhaps as shortening of bumf or bumfodder; def. 2 presumably as shortening of bum bag

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Based on the Random House Dictionary, © Random House, Inc. 2014.
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World English Dictionary
bum1 (bʌm)
slang (Brit) the buttocks or anus
[C14: of uncertain origin]

bum2 (bʌm)
1.  a disreputable loafer or idler
2.  a tramp; hobo
3.  an irresponsible, unpleasant, or mean person
4.  a person who spends a great deal of time on a specified sport: baseball bum
5.  on the bum
 a.  living as a loafer or vagrant
 b.  out of repair; broken
vb (often foll by around) (usually foll by around) , bums, bumming, bummed
6.  (tr) to get by begging; cadge: to bum a lift
7.  to live by begging or as a vagrant or loafer
8.  to spend time to no good purpose; loaf; idle
9.  slang (US), (Canadian) bum someone off to disappoint, annoy, or upset someone
10.  (prenominal) of poor quality; useless
11.  wrong or inappropriate: a bum note
[C19: probably shortened from earlier bummer a loafer, probably from German bummeln to loaf]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Word Origin & History

"buttocks," late 14c., "probably onomatopoeic, to be compared with other words of similar sound and with the general sense of 'protuberance, swelling.' " [OED]

"dissolute loafer, tramp," 1864, Amer.Eng., from bummer "loafer, idle person" (1855), possibly an extension of the British word for "backside" (similar development took place in Scotland, 1540), but more prob. from Ger. slang bummler "loafer," from bummeln "go slowly, waste time." Bum first appears in
a Ger.-Amer. context, and bummer was popular in the slang of the North's army in Amer. Civil War (as many as 216,000 Ger. immigrants in the ranks). Bum's rush "forcible ejection" first recorded 1910. Bummer "bad experience" is 1960s slang.
Online Etymology Dictionary, © 2010 Douglas Harper
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Computing Dictionary

bum definition

1. To make highly efficient, either in time or space, often at the expense of clarity. "I managed to bum three more instructions out of that code." "I spent half the night bumming the interrupt code." In elder days, John McCarthy (inventor of Lisp) used to compare some efficiency-obsessed hackers among his students to "ski bums"; thus, optimisation became "program bumming", and eventually just "bumming".
2. To squeeze out excess; to remove something in order to improve whatever it was removed from (without changing function; this distinguishes the process from a featurectomy).
3. A small change to an algorithm, program, or hardware device to make it more efficient. "This hardware bum makes the jump instruction faster."
Usage: now uncommon, largely superseded by v. tune (and tweak, hack), though none of these exactly capture sense 2. All these uses are rare in Commonwealth hackish, because in the parent dialects of English "bum" is a rude synonym for "buttocks".
[Jargon File]

The Free On-line Dictionary of Computing, © Denis Howe 2010 http://foldoc.org
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American Heritage
Idioms & Phrases


In addition to the idioms beginning with bum, also see on the blink (bum).

The American Heritage® Dictionary of Idioms by Christine Ammer.
Copyright © 1997. Published by Houghton Mifflin.
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Idioms & Phrases
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