CREATOR. A comedian whose audience is afraid to laugh.

H. L. Mencken (1880-1956) American writer and journalist [Henry Lewis Mencken]

A Book of Burlesques, “The Jazz Webster” (1924)
    (Source)

The A Little Book in C Major, ch. 4, § 18 (1916), has an alternate definition. This was expanded in Burlesques to include the above, which then became the sole definition in Chrestomathy, ch. 30 "Sententiae" (1949).

Sometimes misattributed to Voltaire.