When someone is put upon oath, they are required to make a solemn promise to speak the truth. There are several synonyms that can be used to describe this action, such as swearing under oath, taking an oath, making an oath, and pledging under oath. These phrases all mean that the person is bound by an oath, and must adhere to the highest legal and moral standards. Being put upon oath is a serious undertaking, as it carries with it the expectation of accuracy and integrity in all statements made under oath. It is a crucial aspect of many legal proceedings and is taken very seriously by all involved.