shameless
Not feeling bad or guilty about doing something wrong.
Shameless means acting without embarrassment or regret about something that should make you feel ashamed. A shameless person does things they know are wrong, unfair, or inappropriate, but they don't care what others think about it.
When someone cheats openly and doesn't even try to hide it, that's shameless behavior. When a student copies another student's homework right in front of the teacher without any guilt or nervousness, they're being shameless. A shameless liar keeps lying even after being caught, showing no remorse or apology.
The word combines shame (the uncomfortable feeling you get when you've done something wrong) with less (without). So someone shameless acts without shame, like they've turned off the part of themselves that normally says “this is wrong and people will judge me for it.”
Sometimes people use the word more lightly, almost admiringly, when someone pursues what they want with bold confidence: “She had the shameless courage to ask for a raise.” But usually shameless carries criticism. It suggests someone has crossed a line from confident into rude, from bold into inappropriate.
A shameless person doesn't just make mistakes. They openly do wrong things without caring about consequences, fairness, or how their actions affect others.