I. One who joins another in a stipulation, Gai Inst. 3, 110; so id. ib. 3, 117.—Hence,
II. An assistant in a trial, in gen.: “testes tot ... cum adstipulatore tuo comparabuntur?” Cic. Quint. 18, 58; so id. Pis. 9.—And trop., one who assents to or agrees with: “illud falsum esse et Stoici dicunt et eorum adstipulator Antiochus,” Cic. Ac. 2, 21, 67: “vanae opinionis,” Val. Max. 7, 1 fin.