If you rearrange the letters in a word or a phrase and make a new word or phrase - that's an Anagram!

For example:

Listen when rearranged becomes Silent
Butterfly when rearranged becomes Flutter by
Are you leaving? when rearranged becomes Alien voyageur?
A bad loser when rearranged becomes A slob, dear
Very nice when rearranged becomes Even I cry

If you want to try out some anagrams check out
http://www.wordsmith.org/anagram/index.html
and see what you come up with.