To prosecute by law; to commence legal proceedings against a party. It is applied almost exclusively to the institution and prosecution of a civil action. Sue out. To obtain by application; to petition for and take out. Properly the term is applied only to the obtaining and issuing of such process as is only accorded npon an application first made: but conventionally it is also used of the taking out of process which issues of course. The term is occasionally used of instruments other than writs. Thus, we speak of “suing out” a pardon.