noun

a vagrant.

bums had been known to wander up to their door and ask for a sandwich

tramp,vagrant,vagabond,homeless person,derelict,down-and-out,itinerant,traveller,drifter,wanderer,person of no fixed address,beachcomber,ne’er do well,good for nothing,outcast,pariah,beggar,mendicant,hobo,bagman,sundowner,swagman,streety,crusty,bag lady,dosser,derro

verb

get by asking or begging.

they tried to bum money off us

scrounge,beg,borrow,sponge,touch someone for,scab,cadge,sorn on someone for,mooch,bludge

adjective

of poor quality; bad or wrong.

not one bum note was played

bad,poor,inferior,second-rate,second-class,unsatisfactory,inadequate,unacceptable,substandard,not up to scratch,not up to par,deficient,imperfect,defective,faulty,shoddy,amateurish,careless,negligent,dreadful,awful,terrible,abominable,frightful,atrocious,disgraceful,deplorable,hopeless,worthless,laughable,lamentable,miserable,sorry,third-rate,diabolical,execrable,crummy,rotten,pathetic,useless,woeful,lousy,appalling,abysmal,pitiful,godawful,dire,not up to snuff,the pits,duff,chronic,rubbish,ropy,poxy,crap,shit,chickenshit