Source : Webster's Revised Unabridged Dictionary (1913)

Lawful \Law"ful\, a.
   1. Conformable to law; allowed by law; legitimate; competent.

   2. Constituted or authorized by law; rightful; as, the lawful
      owner of lands.

   {Lawful age}, the age when the law recognizes one's right of
      independent action; majority; -- generally the age of
      twenty-one years.