humour [ME] In the Middle Ages scientists and doctors believed that there were four main fluids in the body and that the relative proportions of these determined an individual’s temperament. Blood gave a cheerful or *sanguine disposition; phlegm made somebody stolidly calm or *phlegmatic; choler or yellow bile gave a peevish and irascible, or choleric character; and *melancholy or black bile caused depression. These substances were the four humours, or cardinal humours. From this notion humour acquired the sense ‘mental disposition’, then ‘state of mind, mood’ and ‘whim, fancy’ (hence to humour someone [L16th], ‘to indulge a person’s whim’). The association with amusement arose in the late 17th century. The origin of humour directly refers to fluids—it derives from Latin humor ‘moisture’, from humere ‘to be moist’, source also of humid [LME].