Definition

Excellent, impressive, or exciting; a slang term expressing enthusiasm or approval for something cool or awesome. Originally popularized in 1980s surf and skate culture, it remains a casual way to praise something positively.

Example Usage

That skateboard trick was totally rad!

Origin

Shortened form of 'radical,' which had roots in 1960s counterculture; popularized by 1980s surf and skateboard subcultures, later by Teenage Mutant Ninja Turtles

Fun Fact

The Teenage Mutant Ninja Turtles' catchphrase 'Cowabunga, dude!' was often paired with 'rad,' cementing the term in 1990s youth culture.

Source: Definition backfill (hailey)