Misspelling of knock.

simple past tense and past participle of nock

An ejaculation or orgasm while asleep, often accompanied by an erotic dream.

The physiological perception of pain.

(physiology) The physiological process underlying the sensation of pain.

plural of nocturnal emission

(pharmacology, also attributive) A substance which a patient experiences as harmful due to a previous negative perception, but which is in fact pharmacologically (medicinally) inactive.

(archaic) Hurtful, injurious.

plural of nocebo

(medicine, psychology, psychiatry) A state of agitation or confusion, especially in elderly patients suffering from Alzheimer's disease or other forms of dementia, which begins daily at nightfall and which is alleviated by daylight.