decline — If something declines, it becomes less in quantity, importance, or strength.
decrease — When something decreases or when you decrease it, it becomes less in quantity, size, or intensity.
deduction — A deduction is a conclusion that you have reached about something because of other things that you know to be true.
drop — a small quantity of liquid that falls or is produced in a more or less spherical mass; a liquid globule.
fall — to come or drop down suddenly to a lower position, especially to leave a standing or erect position suddenly, whether voluntarily or not: to fall on one's knees.