Clowning is a term that refers to the act of performing as a clown, or indulging in humorous and playful behaviour. Some possible antonyms for this word could include seriousness, gravity, sobriety, solemnity, severity, or earnestness. These terms suggest a much more sober and sombre attitude, in contrast to the high-spirited and carefree antics of a typical clown. While clowning can often be associated with fun and joy, these antonyms suggest a more austere and disciplined approach. They may be more appropriate in contexts such as business, politics or academic discussions, where a more serious tone is expected.