This acronym comes from Fedora Lady.

SND or So Not Dead: No matter what the bloody scriptwriters choose to do to our beloved RA chaRActers, we know they are, in fact, alive and well and ready to entertain us yet another day.

Some of the characters who have achieved SND status are:

Sir Guy of Gisborne from Robin Hood

Lucas North from Spooks/MI-5

John Porter from Strike Back

To see what these SND characters are up to, check out Fedora Lady’s Sloth Fiction. The first installment can be found here.