Your guest has been waiting for you. (progressive) Waiting for something to happen is part of the job. (gerund) They hurried into the waiting car. (participle used as adjective)
An example of waiting is sitting in a doctor's office for an hour for an appointment.
An example of waiting used as an adjective is in the phrase "a waiting patient."
- In attendance, especially at a royal court.
- in attendance, as on a king or other person of royalty