1. v. to not meet expectations.
2. v. to prevent someone from having intercourse.
1a. Due to your stupidity and lack of attention you really know how to cancel the clown.
1b. Are you feeling ok? Where's your head at? You're really cancelling the clown today.
2a. After dinner last night I thought my girlfriend and I were going to have intercourse, instead she cancelled the clown on me.
2b. I was really getting to know that girl through intense conversation and then my douchebag friends intruded on my squirrel
and cancelled the clown on me.