Yes, thin is a Scrabble word!

Adverb

1. Without viscosity

Adjective

1. Of relatively small extent from one surface to the opposite or in cross section

2. Lacking excess flesh

3. Very narrow

4. Not dense

5. Relatively thin in consistency or low in density; not viscous

6. (of sound) lacking resonance or volume

7. Lacking spirit or sincere effort

8. Lacking substance or significance; a fragile claim to fame"

Verb

1. Lose thickness; become thin or thinner

2. Make thin or thinner

3. Lessen the strength or flavor of a solution or mixture

4. Take off weight