Bulgarian slang. A person who is making you laugh just when you see him.You may name s.o. a "smeshko" just because he is funny-looking or because he has insulted you in some way and you want to answer appropriately.A not very insultive word, more like poking fun.
Goliam si smeshko obache! / You're one hell of a ... .
Mahai se ot tuka be, smeshko. / Get out of here, you ... .