no-show

noun

1. a person who makes a reservation and neither uses nor cancels it.
2. a person who purchases an admission ticket and doesn’t use it.
3. any absentee.

adjective

4. not appearing as scheduled or expected.

noun

1. a person who fails to take up a reserved seat, place, etc, without having cancelled it

n.also no show, “someone who fails to keep an appointment,” 1941, from no + show (v.), in the “show up, appear” sense. Originally airline jargon.