/down"shift'/ , v.i.
1. to shift an automotive transmission or vehicle into a lower gear.
2. to become less active; slow down: The economy seems to be downshifting.
v.t.
3. to shift (an automotive transmission or vehicle) into a lower gear.
n.
4. an act or instance of downshifting.
[ 1950-55; DOWN 1 + SHIFT ]