give (someone) the third degree
To interrogate, scrutinize, or question someone intensely or thoroughly. My boyfriend is so controlling, always giving me the third degree if I go anywhere or see anyone without him. The police gave me the third degree regarding my whereabouts during the crime.
give someone the third degree
If someone gives you the third degree, they ask you a lot of questions in a determined manner. He told the operator his wife was having a baby on the pavement. The operator gave him the third degree to make sure he was serious. The interviewer didn't exactly give her the third degree.