adjective. Fingerprints can be forensic evidence. Fingerprints can be forensic evidence. The definition of forensic is something that is usable in a court of law. An example of forensic used as an adjective is forensic evidence, such as finger prints. Forensic is defined as using technology or science to prove something legally. An example of forensic used as an adjective is forensic science, a type of science which includes ballistics, the study of guns and bullets.