- The definition of facetious is a joke made about something serious.
An example of facetious is someone saying that people whose homes have burned down don't have to worry about whether the housekeeper did a good job.
Origin of facetiousFrench facétieux ; from Classical Latin facetia: see facetiae and amp; -ous
Origin of facetiousFrench facétieux, from facétie, jest, from Latin facētia, from facētus, witty.
(comparative more facetious, superlative most facetious)