smear

To spread or daub (a surface, for example) with a sticky, greasy, or dirty substance.

To apply by spreading or daubing.

To cause to be blurry or spread in unwanted places.

To stain or attempt to destroy the reputation of; vilify.

To defeat utterly.

To spread easily in an undesired way.

A mark made by smearing; a spot or blot.

A substance to be spread on a surface.

A sample, as of blood or bacterial cells, spread on a slide for microscopic examination or on the surface of a culture medium.