Apparently invidious is a word, and even part of a legal term.
https://www.law.cornell.edu/wex/invidious_discrimination

Invidious discrimination is a legal term used to describe the act of treating a class of persons unequally in a manner that is malicious, hostile, or damaging. It refers to discrimination that is motivated by animus or ill will towards a particular group, rather than based on a legitimate , non-discriminatory reason