Source : Webster's Revised Unabridged Dictionary (1913)

Irascibility \I*ras`ci*bil"i*ty\, n. [Cf. F. irascibilit['e].]
   The quality or state of being irascible; irritability of
   temper; irascibleness.

Source : WordNet®

irascibility
     n : a feeling of resentful anger [syn: {short temper}, {spleen},
          {quick temper}]