Definitions:

1. Engaging in playful, boisterous, or silly behavior, often with the intention of making others laugh or attracting attention. VERB
   • He's always clowning around, even in serious situations.
2. To act silly, goof off, or behave in a playful or foolish way, often to entertain others or avoid seriousness. VERB
   • The kids were clowning around in class and got in trouble.

Synonyms:

• acting up
• being silly
• fooling around
• goofing off
• horsing around
• messing around