bum

UK: /ˈbʌm/ US: /bʌm/ ,(bum)

Inflections of 'bum' (adj):

bummer

adj comparative

bummest

adj superlative

Inflections of 'bum' (v): (⇒ conjugate)

bums

v 3rd person singular

bumming

v pres p

bummed

v past

bummed

v past p

WordReference Random House Learner's Dictionary of American English © 2025

bum¹ /bʌm/   n., v., bummed, bum•ming, adj., bum•mer, bum•mest. 
n. [countable]

1. a person who avoids work and lives off others.
2. Informal Terms Informal. a person who is very interested in something;
   enthusiast:
   a ski bum; a beach bum.
3. Informal. an incompetent or worthless person:
   "Get another job, you bums,'' he yelled.

v. 

4. Informal Terms Informal. to borrow (something) without a promise to return:
   [~ + object (+ off + object)] Can I bum a cigarette (off you)?
5. bum around, [no object] [Informal.] to spend time or wander aimlessly:
   All vacation long we just bummed around.

adj. [before a noun] [Slang.]

6. of poor or miserable quality;
   worthless:
   a bum deal on that useless car.
7. false or misleading: A bum rap is when you are falsely accused of something.
8. lame:
   a bum leg.

Idioms

9. Idioms bum (someone) out, [~ + object + out] [Slang.] to disappoint, upset, or annoy:
   That test really bummed me out.

bum² /bʌm/   n. [countable] Brit. Slang.

1. British Terms the buttocks;
   rump:
   falling on his bum.

WordReference Random House Unabridged Dictionary of American English © 2025

bum¹  (bum), n., v., bummed, bum•ming, adj., bum•mer, bum•mest. 
n. 

1. a person who avoids work and sponges on others;
   loafer;
   idler.
2. a tramp, hobo, or derelict.
3. [Informal.] an enthusiast of a specific sport or recreational activity, esp. one who gives it priority over work, family life, etc.:
   a ski bum; a tennis bum.
4. [Informal.] an incompetent person.
5. a drunken orgy;
   debauch.
6. 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.

v.t. 

7. [Informal.] to borrow without expectation of returning;
   get for nothing;
   cadge:
   He's always bumming cigarettes from me.
8. [Slang.] to ruin or spoil:
   The weather bummed our whole weekend.

v.i. 

9. to sponge on others for a living;
   lead an idle or dissolute life.
10. to live as a hobo.
11. bum around, [Informal.] to travel, wander, or spend one's time aimlessly:
    We bummed around for a couple of hours after work.
12. bum (someone) out, [Slang.] to disappoint, upset, or annoy:
    It really bummed me out that she could have helped and didn't.

adj. Slang. 

13. of poor, wretched, or miserable quality;
    worthless.
14. disappointing;
    unpleasant.
15. erroneous or ill-advised;
    misleading:
    That tip on the stock market was a bum steer.
16. lame:
    a bum leg.

• 1860–65, American; perh. shortening of or back formation from bummer¹; adjective, adjectival senses of unclear relation to sense "loafer'' and perh. of distinct origin, originally

Synonyms

• 2. vagabond, vagrant.

bum²  (bum), n. [Chiefly Brit. Slang.]

1. British Terms the buttocks;
   rump.

• 1350–1400; Middle English bom; of uncertain origin, originally

bum³  (bum), n. [Mil. Slang.]

1. Military a reproduction of a document made with copying equipment.
2. Military a bag into which classified waste is put in preparation for destruction.

• def. 2 presumably as shortening of bum bag perh. as shortening of bumf or bumfodder

Collins Concise English Dictionary © HarperCollins Publishers::

bum / bʌm/ noun

1. the buttocks or anus

Etymology: 14th Century: of uncertain origin

bum / bʌm/ noun

1. a disreputable loafer or idler
2. a tramp; hobo

verb (bums, bumming, bummed)

1. (transitive) to get by begging; cadge: to bum a lift
2. (intransitive) often followed by around: to live by begging or as a vagrant or loafer
3. (intransitive) usually followed by around: to spend time to no good purpose; loaf; idle
4. bum someone out ⇒ to disappoint, annoy, or upset someone

adjective

1. (prenominal) of poor quality; useless

Etymology: 19th Century: probably shortened from earlier bummer a loafer, probably from German bummeln to loaf