Merriam-Webster Collegiate Dictionary - temperament

 noun  Etymology: Middle English, from Latin ~um, from temperare to mix, temper  Date: 15th century  1. obsolete  a. constitution of a substance, body, or organism with respect to the mixture or balance of its elements, qualities, or parts ; makeup  b. complexion 1  2. obsolete  a. climate  b. temperature 2  3.  a. the peculiar or distinguishing mental or physical character determined by the relative proportions of the humors according to medieval physiology  b. characteristic or habitual inclination or mode of emotional response a nervous ~  c. extremely high sensibility; especially excessive sensitiveness or irritability  4.  a. the act or process of tempering or modifying ; adjustment, compromise  b. middle course ; mean  5. the slight modification of acoustically pure intervals in tuning a musical instrument; especially modification that produces a set of 12 equally spaced tones to the octave  Synonyms: see disposition