Thugdere is when someone (typically a female character, though it can in some cases be applied to a male) often mistreats their lover, often physically or emotionally harming them, but can also be quite affectionate toward them. The "thugness" is often a way they hide their sweet, caring, and loving side, which they may often think makes them look weak or foolish. Not to be confused with tsundere, kuudere, or yandere.