PRINCIPAL: Three different meanings: First, an adjective describing the most significant thing under discussion. Second, the head administrator of a primary or secondary school. Third, the initial sum of a loan.
PRINCIPLE: A basic rule or standard, particularly a moral or intellectual one.
LOSE: A verb with two chief meanings: First, to fail to keep something. Second, to fail to win something.
LOOSE: An adjective. The opposite of "tight."
DISCRETE: Self-contained or separated from others.
DISCREET: Quiet and tactful.
BREACH: A verb; to break through something.
BREECH: The part of a gun behind the barrel.