1)Somthing you look up in Urban Dictionary when your uncreative brain isn't able to figure out a better definition to look up. As "look up" is written next to the look-up-box.
2) Something you did a few seconds ago,of course after giving this definition a thumb up.
antonym: look down
"I just looked up the term "look up"
What it usualy says before a search box on a dictionary website (on the other side from the search button)
look up and you'll see "Look up" i.e., it's at teh top of this page...
To search online, in a book, magazine, dictionary, encyclopedia, other writing work, for an answer or other need
I will look up this fucking word now:
i am good and fun
i look up and a bird shits on my face
to look up as in to look into the sky retard.