Wiktionary
deboost
vb. To slow a spacecraft, typically in order to achieve a stable orbit
Usage examples of "deboost".
You won't have any problems adjustingour ships boost and deboost at close to a standard G, so you'll have two years of subjective time to toughen up.
At a steady one gravity, boost and deboost, the crossing still took under a week, and meanwhile U.
We deboosted from orbit and entered the Martian atmosphere sixteen days later.