Interviewers are only supposed to ask questions that are directly relevant to the job duties. Whatever the reason for the job gap, there is no possible answer

Interviewers are only supposed to ask questions that are directly relevant to the job duties. Whatever the reason for the job gap, there is no possible answer that is legally permissible. Remember more and more states are banning questions about jail time as well (look up 'ban the box'). So even if the person said, "I spent time in jail" that is still problematic. They may not have been convicted and considered innocent. Background checking services exist for a reason. An interviewer asking about a job gap is already on sketchy legal ground. The interviewer asking an inappropriate question is not entitled to a truthful answer to an inappropriate question that is not related to job qualifications. Here is an example to help understand why this is problematic. Lets say the candidate is religious. They took a year off to go on a missionary trip. If the candidate answers correctly (i.e. doesn't lie) the interviewer just discovered the candidate's religion. This knowledge is now super problematic if the candidate is rejected. This is why good interviewers do not ask about hobbies or what the person does outside of work hours. There is a real risk of discovering protected information (sexual orientation, religion, national origin, marital status, family situation - including plans to have children, etc.). Remember a court of law is going to hear the question and the TMI answer that the candidate felt compelled to supply. The intent of the interviewer will be determined by a court NOT the interviewer.