An indefinite period is a length of time that has no definite end or beginning. It can refer to a span of time that is not specified, or it can refer to a period of time that is ongoing and has no foreseeable end. The term 'indefinite periods' can also be used to describe a situation in which there is no clear answer or resolution. The term 'spells' is often used to refer to a period of time in which something happens repeatedly or for an extended period of time.