IPA: /ˌæn.tiˈhjuː.mən/
KK: /æntiˈhjuːmən/
Opposed to or acting against humanity and human values.
The dystopian novel depicted an antihuman regime that disregarded individual rights.
Antihuman is formed from "anti-" (meaning against) and "human" (from Latin "humanus", meaning human or relating to man). The word describes something that is against or opposed to humanity or human values.
Think of 'anti-' meaning against, and 'human' relating to people — so antihuman refers to something that is against human values.