deboost

To slow a spacecraft by reducing thrust, typically in order to achieve a stable orbit.

This combination would prevent anti-ballistic missile radar (BMEWS), presently the U.S.’s main screen against surprise attack, from ascertaining the point of impact until the rocket “deboosts”-about three minutes and 500 miles from target.

To limit or suppress the reach of an account or post.

In one tweet Elon appears to allude to the fact that Twitter’s internal systems can apply a shadow ban and deboost an account on their own, without any human interference or knowledge. […] Outside of the Twitter Terms of Service there are no guidelines for when or how a user could be shadow banned or deboosted – likely, because until recently most users were unaware that such a thing could occur to them.

And it was not as though they were unable, as the waves of bannings and algorithmic deboosting of those on the online right began in earnest after 2016.

A slowing manoeuvre of this kind.