This is another thread that appeared on the AoPS forums that I'm going to put here.

Simply put, over the summer break, I'll post one word puzzle a day, and along with it, the solution to the previous puzzle.

The puzzle will always involve words or wordplay in some way.

To start:

Puzzle #1 (June 25, 2010)
Level of difficulty: 4/10 (Moderate)

Find the word that acts as a prefix and suffix to each of the following pairs of words. The number of dashes represents the number of letters in the word.

E.g. if the puzzle were "BACK ---- HOLD", the answer would be "HAND" because it forms the words "BACKHAND" and "HANDHOLD".

1. FORE ---- BACK
2. EAR ---- IN
3. DEAD ---- BACKER
4. FALL --- PUT