In lang=en terms the difference between expense and spare
is that
expense is to charge a cost against an expense account; to bill something to the company for which one works while
spare is (
to give up) to deprive oneself of, as by being frugal; to do without; to dispense with; to give up; to part with.
As nouns the difference between expense and spare
is that
expense is a spending or consuming often specifically an act of disbursing or spending funds while
spare is the act of sparing; moderation; restraint.
As verbs the difference between expense and spare
is that
expense is to charge a cost against an expense account; to bill something to the company for which one works while
spare is to show mercy.
As an adjective spare is
scanty; not abundant or plentiful.