1. Verb - to make somebody feel good by clicking the thumb up icon on urbandictionary.com next to a word they have placed there.
2. Noun - a physical inication from another human that something useful and worthwhile has been achieved
1. Yes - somebody thumb up my word at last!
2. She gave me a thumb up for my birthday.
Something you can actually give to your OWN definition on Urban Dictionary!! I tried it.
My positive definition of George W. Bush isn't going so well. It has 300 thumbs down and only one thumb up, and that was mine.