To beat utterly and completely at
something (including and especially life in general).
To get shitslammed:
To perform extremely poorly on a
test. To get beaten badly at a videogame/sport/etc. Basically, to be completely overwhelmed by
something.
"I thought I was going to do well on that
test, but I just got shitslammed."
"I tried to send my knights around to trample his archers, but they got shitslammed by his pikemen before they could
ride ten feet."
"Shitslam that
guy!"