Source : Webster's Revised Unabridged Dictionary (1913)

Corroborative \Cor*rob"o*ra*tive\ (k?r-r?b"?-r?-t?v), a. [Cf. F.
   corroboratif.]
   Tending to strengthen of confirm.

Corroborative \Cor*rob"o*ra*tive\, n.
   A medicine that strengthens; a corroborant. --Wiseman.

Source : WordNet®

corroborative
     adj : serving to support or corroborate; "collateral evidence"
           [syn: {collateral}, {confirmative}, {confirming}, {confirmatory},
            {corroboratory}, {substantiating}, {substantiative}, {validating},
            {validatory}, {verificatory}, {verifying}]