A word used in Beck's train of thought surreal song Hotwax from the album 'Odelay'. His train of thought was kinda Kenny Rogers, barflys and stretch wrangler jeans in the mood to impress. Eeewww....

Tight, stretchy pants meant to show-off one's ass. Typically worn by college hoochies out clubbing.

cheaply constructed polyester/lycra pants easily distinguished by lack of back pockets. asspants are typically tight around the posterior and thigh areas, with a tacky 'flare' from the knee down. despite being available in an array of colors, the most commonly adorned pairs are black, followed by white. asspants are typically worn by clueless women with low self-esteem who attend clubs and bars in search of horny men. woo-girls are typically the greatest offenders.

Pants that has the back end or seat of them cut out where it will show your bare ass. Ass pants are always worn without underwere.
Often worn by queers.
Also worn by women when they want to show off there ass to men.