Downvote, dislike, disapprove, condemn, criticize, defame, discredit, reprimand, rebuke, reproach, censure, denounce, pan, decry, depreciate, disparage, devalue, vilify, defile and reject are all antonyms for the word "upvote." Antonyms are words with opposite meanings to a particular word. Upvote can be defined as an online system used to indicate agreement or approval for a post or comment. Conversely, the antonyms indicate disagreement or disapproval for the same. In contrast to upvote, downvote is the most commonly used antonym, which denotes the opposite meaning of showing disapproval.