From Merriam-Webster

Main Entry: Bum
Function:noun
Etymology:
Middle English bom
Date:
14th century

Function:adjective
1 a: of poor quality or nature "bum advice"
b: not valid or deserved "a bum check"
c: not pleasant or enjoyable "a bum trip"
2. affected or disabled by damage or injury

Function:verb
1. loaf
2. to spend time unemployed and often wandering
transitive verb: to obtain by asking or begging
cadge "bum a cigarette"

Function:noun
1 a: one who sponges off others and avoids work
b: one who performs a function poorly "called the umpire a bum"
c: one whose time is devoted to a recreational activity
"a beach bum" "ski bums"

"Climbing Bums"