When a contestant on a reality show does really well one week, but gets voted out the following week.
Derived from the show America's Next Top Model, when a contestant named "Clark" recieved a first place call out one week, but was eliminated the following week.
Jaclyn was doing really well in the competition, but the she got clark'd.
When one performs a sexual action and it is not reciprocated.
I totally got Clark'd last night. You've just been Clark'd.