The peculiar physical and mental character of an
   individual, in olden times erroneously supposed to be due to individual
   variation in the relations and proportions of the constituent parts of
   the body, especially of the fluids, as the bile, blood, lymph, etc.
   Hence the phrases, bilious or choleric temperament, sanguine
   temperament, etc., implying a predominance of one of these fluids and a
   corresponding influence on the temperament.