IPA: /dɪˈsɜːrtɪfaɪ/
KK: /dɪˈsɜr.tɪ.faɪ/
To take away the official approval or certification from something or someone.
The organization decided to decertify the training program due to safety concerns.
Past: decertified
Past Participle: decertified
Decertify → It is formed from "de-" (meaning down or away) and "certify" (from Latin "certificare", meaning to make certain or to confirm). The word "decertify" means to remove the certification or to take away the confirmation of something.
Think of 'taking away' ('de-') the 'confirmation' ('certify') — that's why decertify means to remove a certification.