Stiffness
Stiffening, Rigidity
noun, verbal noun
Keep something stiff and straight and it's naturally going to lead to stiffness or stiffening.
硬直 commonly describes a person's body becoming stiff, whether from shock or discomfort, or due to the onset of rigor mortis following death.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
心理的硬直は問題を解決する妨げになると思われる。
I believe that psychological rigidity can hinder problem solving.
社会の硬直化は解決しなければならない問題です。
The rigidity of society is a problem that we need to fix.
死後どのぐらいで死後硬直が起きるんでしょうか。
I wonder how long after death rigor mortis sets in.