humourous

From humour +‎ -ous.

humourous (comparative more humourous, superlative most humourous)

1. (chiefly UK, uncommon, proscribed) Alternative spelling of humorous
   • 1731 (date written), Simon Wagstaff [pseudonym; Jonathan Swift], “An Introduction to the Following Treatise”, in A Complete Collection of Genteel and Ingenious Conversation, […], London: […] B[enjamin] Motte […], published 1738, →OCLC, page xiv:

     [W]hatever Perſon vvould aſpire to be completely vvitty, ſmart, humourous, and polite, muſt by hard Labour be able to retain in his Memory every ſingle Sentence contained in this VVork, […]

• The Oxford Dictionary states that "the spelling humourous is regarded as an error" in both British and American English.[1]