Definition of isolation

This is important if you've ever had the feeling of being alone in a
crowded room.

To the observer it looks like that isn't a state of isolation because
there are people around (in simplistic terms). An individual with a good
mask will look like they're social and engaging with their social
environment. It doesn't mean they don't feel alone and isolated.

Considering accurate definitions is beyond my capability this morning
but I'm sure this will start a thought process.