The Collaborative International Dictionary of English v.0.48:

Spitfire \Spit"fire`\, n.
   A violent, irascible, or passionate person. [Colloq.]
   --Grose.
   [1913 Webster]

WordNet (r) 3.0 (2006):

spitfire
    n 1: a highly emotional and quick-tempered person (especially a
         girl or woman)

Moby Thesaurus II by Grady Ward, 1.0:

60 Moby Thesaurus words for "spitfire":
   Mafioso, Young Turk, battle-ax, beast, beldam, berserk, berserker,
   bitch, bomber, brute, cat, common scold, demon, devil, dragon,
   fiend, fire-eater, firebrand, fishwife, fury, goon, gorilla,
   gunsel, hardnose, hell-raiser, hellcat, hellhound, hellion,
   holy terror, hood, hoodlum, hothead, hotspur, incendiary, killer,
   mad dog, madcap, monster, mugger, rapist, revolutionary, savage,
   scold, she-devil, she-wolf, shrew, termagant, terror, terrorist,
   tiger, tigress, tough, tough guy, ugly customer, violent, virago,
   vixen, wild beast, witch, wolf