Political Correctness (politically correct or PC), describes how much tolerance, sensitivity, censorship, and freedom of expression “is correct” in a given setting.
Bias is a prejudice for or against. In broad terms we can think of our entire neurology as a system of hardwired and softwired bias. Given this, it is vital to understand that bias isn’t “a bad thing” and is rather an integral part of our cognitive process.
“Useful Idiot” is a political insult that describes a person who, through manipulation or not, is useful to a political cause that is not their own despite not fully realizing their role.
An “in-group” is a group you are part of (genetically, culturally, or ideologically), while an “out-group” is a group you aren’t part of.
The left-right political spectrum is used to create a model that shows a spectrum of political positions. Traditionally there is a 2-axis spectrum of left and right, but there are also many widely adopted 4-axis model.