nod

sense 1: express or signify by nodding; "He nodded his approval"
nod

sense 2: lower and raise the head, so as to indicate assent
nod

sense 3: let the head fall forward through drowsiness; "The old man was nodding in his chair"
nod

sense 4: sway gently back and forth, as of flowers or tress in the wind
nod sway

sense 5: be almost asleep; "The old man sat nodding by the fireplace"
nod