What It Scores
RIZ is a valid word in the tournament list this site uses. Tile values only, before any premium square: 12 in Scrabble and 12 in Words With Friends. The letters break down as R1 I1 Z10.
Longer Words Containing RIZ
RIZ appears inside each of these, which is what makes it worth knowing as a hook.
Next: the Word Unscrambler for any letters at all, and the two and three letter lists. Full entry and definition at Merriam-Webster.