to make something less effective or spoil it 削弱〔某物〕的效能;破坏,损害
Examples from the Corpus
vitiate• Sadly, they are vitiated by technical problems.• Changes at this point may actually vitiate the entire system.• The attempt to do just this, pursued with inappropriateinsistence, ultimately vitiated the Leavisite campaign.• Also, if the material is soft it may buckle easily at the inner side of the bend and vitiate the result.
Originvitiate
(1500-1600)Latin past participle of vitiare, from vitium; → VICE