How do you change weary into an abstract noun?

The noun form of the adjective 'weary' is weariness. The noun 'weariness' is an abstract on concrete noun depending on the context in which it is used.

The noun weariness is an abstract noun as a Word for a dull and listless state of mind; reluctance to see or experience any more of something.

The noun weariness is a concrete noun as a Word for temporary loss of strength and energy resulting from hard physical work.