C / cautor
noun

cautor

gen. cautōris · gender masculine · decl. 3rd
One who is on his guard; is wary
One who is on his guard or is wary, Plaut. Capt. 2, 2, 6.—
One who is surety; bail for any one
One who is surety or bail for any one, Cic. Sest. 7, 15.