Yes, sweet is a Scrabble word!

Adverb

1. In an affectionate or loving manner (`sweet' is sometimes a poetic or informal variant of `sweetly')

Adjective

1. Having or denoting the characteristic taste of sugar

2. Having a sweet nature befitting an angel or cherub

3. Pleasing to the ear

4. Pleasing to the senses

5. Pleasing to the mind or feeling

6. Having a natural fragrance

7. (used of wines) having a high residual sugar content

8. Not containing or composed of salt water

9. Not soured or preserved

10. With sweetening added

Noun

1. English phonetician; one of the founders of modern phonetics (1845-1912)

2. A dish served as the last course of a meal

3. A food rich in sugar

4. The taste experience when sugar dissolves in the mouth

5. The property of tasting as if it contains sugar