to make a slight, quick downward bending forward of the head, as in assent, greeting, or command.

to let the head fall slightly forward with a sudden, involuntary movement when sleepy.

to doze, esp. in a sitting position

The speaker was so boring that half the audience was nodding.

to become careless, inattentive, or listless; make an error or mistake through lack of attention.

(of trees, flowers, plumes, etc.) to droop, bend, or incline with a swaying motion.

to bend (the head) in a short, quick downward movement, as of assent or greeting.

to express or signify by such a movement of the head

to nod approval; to nod agreement.

to summon, bring, or send by a nod of the head.

to cause (something) to lean or sway; incline.

a short, quick downward bending forward of the head, as in assent, greeting, or command or because of drowsiness.

a brief period of sleep; nap.

a bending or swaying movement. ?

nod off, to fall asleep or doze, esp. in a sitting position

He was reprimanded for nodding off in class.

nod out, Slang . to fall asleep, esp. owing to the effects of a drug. ?

give the nod to

Informal . to express approval of; agree to

The board gave the nod to the new proposal.

on the nod

British Slang . on credit.

Slang . drowsy following a dose of a narcotic drug.

adjective

dozy , drowsy , slumberous , slumbery , somnolent , soporific