Source : Webster's Revised Unabridged Dictionary (1913)

Illegality \Il`le*gal"i*ty\, n.; pl. {Illegalities}. [Cf. F.
   ill['e]galit['e].]
   The quality or condition of being illegal; unlawfulness; as,
   the illegality of trespass or of false imprisonment; also, an
   illegal act.