lit‧ter‧bug /ˈlɪtəbʌɡ $ -ər-/ (
also ˈlitter lout British English)
 noun [countable] informal someone who drops paper, cans etc on the ground in public places 
 [TahlilGaran] Dictionary of Contemporary English ▲
 litterbug n., 
slang, 
informal A person who leaves garbage in a public place, such as a park or beach or a street; one who litters. 
 Don't be a litterbug; keep the city clean!
 Don't be a litterbug; keep the city clean!  [TahlilGaran] English Idioms Dictionary ▲