(verb)
(American) to shift a bicycle or an automotive vehicle to a lower gear;
e.g. You can downshift the car once you are driving slower.
(noun)
an instance of something decreasing in intensity, amount, or quality, such as an instance of switching from a high-paying but stressful job to a lower-paying but more relaxed and fulfilling one;
e.g. The economy saw a downshift due to the oil shortage.