Sticker \Stick"er\, n.

1. One who, or that which, sticks; as, a bill sticker.

2. That which causes one to stick; that which puzzles or poses. [Colloq.]

--Tackeray.

3. (Mus.) In the organ, a small wooden rod which connects (in part) a key and a pallet, so as to communicate motion by pushing.

4. Same as Paster, 2. [Political Cant, U.S.]

Source: Webster's Revised Unabridged Dictionary (1913)