What It Scores
GHYLL is a valid word in the tournament list this site uses. Tile values only, before any premium square: 12 in Scrabble and 13 in Words With Friends. The letters break down as G2 H4 Y4 L1 L1.
Longer Words Containing GHYLL
GHYLL 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.