SPELLBOUND
Credit: GAMES Magazine - Dec. 1998
Darren Rigby  (adapted)

A certain eight-letter word contains no repeated letters. The words in the left-hand column below can be spelled entirely with the letters from this word. The words in the right-hand column contain some letters from this word, but also contain letters which are not found in this word. What's the word?

FOLD       DEFT
LONE       FLIT
FUEL        RIDE
RUDE       DUAL   
UNDO      LOAN
LEND       TOLD

HINT:
Any letters in the right-hand column which are not found in the left-hand column can be eliminated.

Answer:
The word is FLOUNDER.