Definitions by Starfleet Command

Skimming Atmosphere 

When an extreme act is taken right upto the limit, but backed off at the last moment.

"That was so close, we were almost skimming atmosphere there."

Skimming Atmosphere by Starfleet Command March 6, 2022

Frakes 

When a guest actor or celebrity tells fans they are going to be at a convention or show, then cancel just before the event.

In common usage by UK and European attendees of Science Fiction conventions.

Looks like another guest has pulled a Frakes!

Frakes by Starfleet Command March 3, 2017