(noun) A terrible joke, often where the teller of the joke will not, or frankly refuses to achknowledge his/her non-existent sense of humor. The teller of a 'jiwoo' usually includes lame references to explosions or crashes, and will continue telling the course of a joke to the point where it isnt funny anymore, often taking lengths to then explain the joke to his/her friends. A frequent teller of 'jiwoo's may also be referred to as a 'Jiwoo' him/herself
Guy 1: So like. imagine this train suddenly crashed into this classroom and it was like 'boooooooom'
Guy 2: dude, that was a jiwoo
Guy 1: And then like, everyone was like 'ahhh...kaboooom'
Guy 2: you are such a jiwoo man