from The American Heritage® Dictionary of the English Language, 4th Edition
- adv. In the very act of committing an offense; red-handed.
- adv. In the act of having sex.
from The Century Dictionary and Cyclopedia
- While the crime is (or was) being committed; while the crime is (or was) in the very performance: as, he was apprehended flagrante delicto.
Medieval Latin flagrante dēlictō, while the crime is blazing : flagrante, ablative of flagrāns, blazing + dēlictō, ablative of dēlictum, offense.(American Heritage® Dictionary of the English Language, Fourth Edition)