nod

A sign of assent or salutation or command.

The act of nodding the head.

Be almost asleep.

“The old man sat nodding by the fireplace”

Express or signify by nodding.

“He nodded his approval”

Lower and raise the head, as to indicate assent or agreement or confirmation.

“The teacher nodded when the student gave the right answer”

Sway gently back and forth, as in a nodding motion.

“the flowers were nodding in the breeze”

Let the head fall forward through drowsiness.

“The old man was nodding in his chair”