to refuse to have, take, recognize, etc.

to reject the offer of a better job.

to refuse to grant (a request, demand, etc.).

to refuse to accept (someone or something); rebuff

The other children rejected him. The publisher rejected the author's latest novel.

to discard as useless or unsatisfactory

The mind rejects painful memories.

to cast out or eject; vomit.

to cast out or off.

Medicine/Medical . (of a human or other animal) to have an immunological reaction against (a transplanted organ or grafted tissue)

If tissue types are not matched properly, a patient undergoing a transplant will reject the graft.

something rejected, as an imperfect article.