adjunct (similar term)
ancillary (similar term)
adjuvant (similar term)
appurtenant (similar term)
auxiliary (similar term)
accessary (similar term)
accessory (similar term)
certificatory (similar term)
collateral (similar term)
confirmative (similar term)
confirming (similar term)
confirmatory (similar term)
corroborative (similar term)
corroboratory (similar term)
substantiating (similar term)
substantiative (similar term)
validating (similar term)
validatory (similar term)
verificatory (similar term)
verifying (similar term)
demonstrative of (similar term)
encouraging (similar term)
supporting (similar term)
positive (related term)
unsupportive (antonym)