Jocular – jocose (given to jokes and jesting); waggish; merry; given to jesting; joking; humorous; full of fun; said as a joke

She stopped short as a violent peal sounded on the front-door bell.

“An impatient patient, I expect,” I murmured jocularly.

“I’m afraid not, my dear Jotson,” replied Sholmes.

The Complete Casebook of Herlock Sholmes, Charles Hamilton, 1921