Worsen
Part of speech: verb
Definition: To make worse. To become worse; to get worse.
Decline
Part of speech: noun
Definition: Downward movement, fall.A sloping downward, e.g. of a hill or road.A weakening.A reduction or diminution of activity.
Part of speech: verb
Definition: To move downwards, to fall, to drop.To become weaker or worse.To refuse.To list the inflected forms of a noun, pronoun (and in some languages adjective) for case and number.
Example sentence: I would suggest that faith is everyone's business. The advance or decline of faith is so intimately connected to the welfare of a society that it should be of particular interest to a politician.