Gloomy and glum are the opposite of cheerful. They begin with the letter G.
Glut
Given
Jovial or cheerful.
The opposite of "bright" is usually "dim." The "g" may be incorrect.
Appealing, bright, comfortable, nice, pleasant, sunny...
happy, cheerful, elated. calm.
One antonym for clumsy is graceful.
Opposite of happy starting with G? Easy — “Grumpy.” But don’t worry, Angel Therapy can help turn grumpy into giggly real quick.
Cheerful, elated and happy. Comforted, joyful and pleased.
riant
In Cinderella, the mouse sidekick starting with "G" is Gus, short for Gus Gus. He is one of Cinderella's loyal friends who helps her throughout the story, particularly in her efforts to attend the royal ball. Gus is known for his cheerful personality and clumsy antics, making him a beloved character in the tale.
Sombre means to be gloomy, dull or solemn. The opposite therefore is is to be bright and breezy, cheerful, happy, lighthearted and generally in a happy mood.