If something is surfy, it is related to surfing or feels like surfing.
Surfy things make people think of the beach, waves, and fun.
Examples:
The surfy music made me want to go to the beach.
Her surfy clothes looked like she just came from the ocean.
The surfy feeling of the movie made me want to learn to surf.
The surfy vibe of the party made everyone want to dance.
The surfy atmosphere at the beach was so exciting!
The surfy waves were perfect for surfing.