unforgivingness

adjective

1. not disposed to forgive or show mercy; unrelenting.
2. not allowing for mistakes, carelessness, or weakness: the unforgiving nature of aviation.

adjective

1. not willing to forgive; unmerciful
2. (of a machine, system, etc) allowing little or no opportunity for mistakes to be corrected
3. harsh and unremittingan unforgiving and desolate landscape

adj.1713, from un- (1) “not” + present participle of forgive.