inclement

Stormy.

Showing no clemency; unmerciful.

Not clement.

Not clement; destitute of a mild and kind temper; void of tenderness; unmerciful; severe; harsh.

Physically severe or harsh (generally restricted to the elements or weather); rough; boisterous; stormy; rigorously cold, etc..

Stormy, of rough weather

Merciless, unrelenting.

unmercifully severe in temper or action

(of weather or climate) severe

used of persons or behavior; showing no clemency or mercy