irascible

irascible (http://definr.com/irascible)

     adj 1: quickly aroused to anger; "a hotheaded commander" [syn: choleric,
             hotheaded, hot-tempered, quick-tempered, short,
             short-tempered]
     2: characterized by anger; "a choleric outburst"; "an irascible
        response" [syn: choleric]