What It Scores
LUCK is a valid word in the tournament list this site uses. Tile values only, before any premium square: 10 in Scrabble and 12 in Words With Friends. The letters break down as L1 U1 C3 K5.
Longer Words Containing LUCK
LUCK appears inside each of these, which is what makes it worth knowing as a hook.
Next: the Word Unscrambler for any letters at all. Full entry and definition at Merriam-Webster.