Though the stick is separate from the man, it separates him from other men without such sticks. As such this is extrinsic definition. Rajwartik also explains the situation by the two examples of fire and warmth and stick and the man holding it. Intrinsic definition, being the nature of the object is the real definition. Externally existing things can be recognised by this only.
Extrinsic definition is from the point of view of associations.
It, therefore, serves the temporary purpose of the object with the association as distinct from the objects without such association. Intrinsic definition is fruitful in defining eternal objects having no associations. The soul, without any such affiliations, can only be defined by such a definition. It is very necessary to be very careful while arriving at the definition of particular objects, because the definition becomes the basis of its analysis. If the definition is defective it would not be able to stand the cannons of' its analysis and examination and would be proved wrong.