When Urban Dictionary makes an attempt at humour by putting more fake downvotes to make it seem as though there are more downvotes for the definition of this word than upvotes.
A button you can click if you disagree with the information or disliked something. It can also give you the temptaion to dislike when you liked it because so many people disliked or downvoted it.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).