In flagrante delicto (Latin for "in blazing offence"), sometimes simply in flagrante ("in blazing"), is a legal term used to indicate that a criminal has been caught in the act of committing an offence (compare corpus delicti). The colloquial "caught red-handed" and "caught rapid" are English equivalents.[1][2]
Aside from the legal meaning, the Latin term is often used colloquially as euphemism for someone being caught in the midst of sexual activity.[3][4]
if somebody is found or caught in flagrante, they are discovered doing something that they should not be doing, especially having sex
2 : in the midst of sexual activity