Humour  (us humor) —n. 1 a quality of being amusing or comic. B the expression of humour in literature, speech, etc. 2 (in full sense of humour) ability to perceive or express humour. 3 state of mind; inclination (bad humour). 4 (in full cardinal humour) hist. Each of the four fluids (blood, phlegm, choler, melancholy), thought to determine a person's physical and mental qualities. —v. Gratify or indulge (a person or taste etc.).  out of humour displeased.  humourless adj. [latin humor moisture]