Humorless

Adjective

 * 1) Lacking humor or levity; serious; not funny, amusing, amused, or lighthearted.
 * He watched the little dog's antics with a humorless stare.

Thesaurus
cheerless, discontented, grim, in bad humor, infestive, joyless, mirthless, miserable, out of humor, out of sorts, pleasureless, sorry, sorryish, uncheerful, uncheery, unhappy, unjoyful, unmirthful, unsmiling, wretched

Alternative forms

 * humourless

Etymology
From.