How many words start with GY?

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

What is the highest scoring word that start with GY?

GYOZA at 18 points in Scrabble, and GYOZA at 18 in Words With Friends, because the two games score the tiles differently.

GYALS, GYBED, GYBES, GYELD, GYMPS, GYNAE, GYNIE, GYNNY, GYOZA, GYPPO and 11 more on this page.

Yes, 4: GYMPS, GYNNY, GYPPY, GYPSY.

There are 21 of them. The highest scoring is GYOZA at 18 points in Scrabble, and the set averages 11.2.

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.

GYPSY noun a laborer who moves from place to place as demanded by employment
GYBED verb form of GYBE: shift from one side of the ship to the other
GYBES verb form of GYBE: shift from one side of the ship to the other
GYRAL adjective relating to or associated with or comprising a convolution of the brain
GYRES noun form of GYRE: a round shape formed by a series of concentric circles (as formed by leaves or flower petals)
GYROS noun form of GYRO: a Greek sandwich: sliced roast lamb with onion and tomato stuffed into pita bread
GYRUS noun a convex fold or elevation in the surface of the brain

Definitions from Open English WordNet, CC BY 4.0.

All of them: Word lists.