"Third-degreeing" is a term often used to describe intense questioning or interrogation in which someone is subjected to pressure in order to get them to reveal information. While this is a common phrase, there are plenty of other synonyms that can be used depending on the context. Some of these include "grilling," "pressuring," "badgering," and "probing." Other terms used in law enforcement or military contexts might include "debriefing," "investigating," or "extracting information." Whatever term is used, it's important to recognize that these types of tactics can sometimes be unethical, and it's important to use discretion when attempting to gather information or intelligence.