Unstick is a 7 letter English word. It's valid Scrabble word worth 13 points. It's valid Words with friends word worth 16 points.
You can make 158 anagrams from letters in unstick (ciknstu).
First recorded in 1700-10; un-2 + stick2
And, come to that, I don't need to unstick the envelope to know what's inside here.
13
16