How many words start with SMA?

10, from 5 letters up to 5. All of them are on this page.

What is the highest scoring word that start with SMA?

SMAZE at 16 points in Scrabble, and SMAZE at 17 in Words With Friends, because the two games score the tiles differently.

SMAAK, SMACK, SMAIK, SMALL, SMALM, SMALT, SMARM, SMART, SMASH, SMAZE.

10 of them: SMAAK, SMACK, SMAIK, SMALL, SMALM, SMALT, SMARM, SMART, SMASH, SMAZE.

There are 10 of them. The highest scoring is SMAZE at 16 points in Scrabble, and the set averages 10.0.

Most common words first, then the rest A to Z.

The most familiar words on this page and what they mean. Tap any word for its full entry, score and anagrams.

SMALL adjective limited or below average in number or quantity or magnitude or extent
SMART adjective showing mental alertness and calculation and resourcefulness
SMASH verb hit with great force
SMACK noun a blow from a flat object (as an open hand)
SMARM noun excessive but superficial compliments given with affected charm

Definitions from Open English WordNet, CC BY 4.0.

All of them: Word lists.