It is all about gestures and not uttering a word.
If you agree, you nod i.e. move your head up and down. But what if you don't agree? Do we have a word to describe the gesture?
In short, what's opposite to 'nodding'?
Actually, the Indian Head Shake is 'YES'; so, getting confused!
You Shake your head.
Not to confuse with banging your hair around to the rhythm of music, or shaking water off your hair, you can add shake your head "no".
That depends on what you mean by don't agree.
If you mean disagree; give a negative response; say no, then you shake your head. This is the opposite of nodding (meaning it gives the opposite response; negative and affirmative, respectively) and different from the Indian head shake. In English, shaking your head means turning it side to side (to the right and left) a few times. It's a rotation around the vertical axis only; the head does not tilt or change its angle relative to the ground (assuming you're standing or sitting straight up). Here's a picture:
From left to right, these are:
But, if you mean express that you don't assent or agree but also don't necessarily disagree; are hesitant, unsure, or of no particular opinion, then you shrug. This necessarily involves raising the shoulders, but lifting the arms and/or a certain kind of facial expression are usually also involved. For example, if you're at the cinema with the man pictured below and had just said what do you want to see? XYZ looks really good!, you'd know that he doesn't agree with you, but doesn't particularly object to seeing XYZ either.
One important thing to remember is that nonverbal communication is not necessarily the same across cultures, even when the language of choice is. In some places shaking your head means yes, so the natives there might misunderstand you even if you're having a conversation in fluent English.
You can use "shake".This is not the opposite but you can use it like this.
This is a common phenomenon in most languages. It is an 'elliptical' phrase, which is derived from 'ellipsis', not 'squashed circle shape'. It means that part of the phraseology is left unspoken (elided), but the semantic content is 'understood' by the hearer/reader because they are familiar with the usage within that context.
The actual comparison in this instance of the phenomenon should be, "if you agree you 'nod [your head]'; if you disagree, you 'shake your head'. This correctly puts the emphasis on the use of 'nod' and removes it from 'shake'. And that eliminates most of the discussion of cultural and colloquial meanings and focuses attention on language structure, not usage.
If you become sensitive to this phenomenon, you will begin to notice its very ubiquitous influence. Almost every conversation you have will include, and most understandings will often hinge on, differing interpretations of statements in which elliptical phrases are central to the semantics.
It is also the foundation of most advertising slogans and almost all jokes. Which means it also has both visual and conceptual parallels. The basic proposition is that the context of our communication (meaning the conceptual grasp we have of our physical and intellectual environment) is subject to change based on the definitions that participants in a communication impose on the other participants. And it is proof that often the power and influence of a statement is based not on what is said, but what is not said. So a powerful or inspiring statement could build up a motivating context which the hearers might tend to identify with and then some aspect of the context can be left 'open' (the future, the contingencies, the key contribution, the missing link) and each listener then completes their internal context by filling in their personal impression of that unspoken item.
Salvador Dali's 'surrealism' is the most 'graphic' graphic example of the principle: introducing contrasting items will change our perception by altering the context of our internal, mental environment. The image is simply lines, spaces, and paint, but the semantics that Dali introduces forces the viewer to examine the process of how they internally assemble a semantic context of their moment-by-moment experience.
In the same way, a joke sets up a context that seems to mean one thing, but the punchline reveals that the context can and should be interpreted as something else entirely.
So the elliptical phrase is a key part of influencing people since it one of those flexible and malleable (can bend, can BE bent) components in the language capability that underlies all languages and constitutes the underlying logic that humans were given at their creation.
