1. superlative form of inhuman; most lacking in compassion, kindness, or human feeling; most cruel or brutal
Usage: superlative degree; formal or literary register

Examples

• The inhumanest treatment of prisoners was documented by human rights organizations.
• His inhumanest actions during the conflict shocked the international community.
• She condemned the inhumanest practices as violations of basic human dignity.
• The inhumanest conditions in the facility were exposed by investigators.
• Of all the regimes studied, historians considered that one the inhumanest.