(third-person singular simple present shakes one's head, present participle shaking one's head, simple past shook one's head, past participle shaken one's head)
- To move one's head from side to side, in a repeated swiveling motion from the neck, to indicate disagreement, negation, disbelief, or dismay.
- (less common) To move one's head up and down, in a repeated hinge-like motion from the top of the spine, to indicate agreement, affirmation, approval, or simply polite attentiveness.
- A relatively quick head movement from side to side indicates an emphatic "no," while a slower motion tends to indicate disbelief or dismay.
- A relatively quick head movement up and down indicates an emphatic "yes," while a slower motion tends to indicate attentiveness.
- In some countries, for example in Bulgaria and Sri Lanka, the meanings are reversed: i.e. a movement side to side means "yes" and a movement up and down means "no"