A jocular imposition, the same as a humbug.
See humbug.
·noun An imposition; a cheat; a hoax. II. Bam ·vt To <<Cheat>>; to <<Wheedle>>. ...
Webster's Dictionary of the English Language
To impose on any one by a falsity; also to jeer or make fun of any one. ...
Dictionary of The Vulgar Tongue by Francis Grose