When talking about the Urban Dictionary ratings system, the opposite of the thumbs up. Where a thumbs up denotes a good definition and thumbs down denotes a bad one. There aren't many definitions out there whcih don't have at least one thumbs down. Whether or not people actually like a definition, they will give it a thumbs down, because they hate everybody, the world is unfair to them and they like to cut themselves.
Only assholes give definitions the thumbs down, unless it really sucks.
1) what you give when someone says or does something you don't like
2) what annoying people give to your comments to make their comments stand out
p.s. look at the example