capitalis (kap-i-tay-lis), adj.[Latin] 1.Roman law. (Of a crime) punishable by death, loss of liberty, or loss of citizenship. See CAPUT. 2.Hist. (Of a person or judicial proceeding) that is principal or chief. capitalis,n.[Latin “chief”] Hist. A principal (or chief) person, object, or judicial proceeding. [Blacks Law 8th]