verb: gave a rating of "1"(out of some number) to something.
Used to indicate
major suckage or disapproval.
The opposite might be "5'd" or "
10'd" if the maximum possible rating was, respectively,
5/5 or 10/10.
Often seen in reference to a
YTMND animation/page, where users are encourage to rate YTMND creations on a
scale of 1-5 stars:
"That was totally lame.. I just 1'd it".