As a rule a material that is very tacky has no inner consistency and therefore no cohesion, like e.g. honey. Still for raw uneven and dusty surfaces a tacky material is often used. The tack can be measured with a rolling ball test.
By cohesion is meant the inner density of a material, e.g. split resistance or also shear resistance. Adhesives with little cohesion leave glue rests when being removed.