DECREASE v. 2 definitions
to increase; to be diminished gradually, in size, degree, number, duration, etc., or in strength, quality, or excellence; as, they days decrease in length from June to December. He must increase, but I must decrease. John iii. 30.
DILUTE v.
To diminish the strength, flavor, color, etc., of, by mixing; to reduce, especially by the addition of water; to temper; to attenuate; to weaken. Lest these colors should be diluted and weakened by the mixture of any adventitious light. Sir I. Newton.