Overshoot Animation
A word most commonly used by 2D animators is 'overshoot' animation. This aspect is also very important for 3D animators as it adds more liveliness and bounciness to the characters.
The meaning of the term 'Overshoot' is going beyond your final position and then come back to the final position and settle down.
You will see overshoot applied to motion graphics a lot, as it give a good finish to the texts, images or even 2d character animation. Here is an example of a motion graphics overshoot.
Overshoot can be of two types, 'Tangent' overshoot and overshoot that is directly added to the character.
I have shown both the examples in the video and have explained how it can be done. Overshoot creates a bounciness in the character that makes the character more alive.

For tangent overshoot, manipulating the curves of the object/character animation and making a curve like the above shown image will make you object go beyond the position and come back and settle. The higher the curve goes, the further the object will go far away from the final position.
You can test this by simply using a ball animation. You can animate it from left to right and then manipulate the curve before the final position (like the above shown image) and see the difference.

To apply overshoot directly on the character you can use the final pose key frame and copy and paste it to the overshoot pose. Then manipulate and exaggerate the overshoot pose and then settle back to the final position again. In this way you can apply overshoot to your character animation very easily.