Severity
Rigor, Cruelty, Harsh
noun, な adjective
Your boss surpasses his normal cruelty and rains severity down on your head. You had other things to do this weekend and now you have to work through it? Harsh...
かこく
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
彼らは、不当に過酷な労働を強いられています。
They’re being forced into unreasonably severe manual labor.