Smear is when an animation leaves a "trail" behind that makes the image stretch from their previous position. This is a trick widely used in animation that makes it feel much more natural.
Without Smear
With Smear
Property
Description
Precision
The precision of the smear trail. Low precision will make the trail be more noticeable.
Trail
How long the smear trail will be.
Inline
If the image has an outline, setting an inline value bigger than the outline will make the smear only use the inside part of the image.
Render Mode
Defines where the trail is created. The options are Front and Back.