Hi
In the sequence that you described I would be more concerned with how I framed and lit the shot. I would use simple action words such as "Pensive" but I would add a decisive direction in which the character would look for it to create the particular feel that I would want to create.
Before I'd do any of this I'd make sure that the actor understood the scene fully and I would show them how I would frame it in a proper storyboard. If that didn't work I would get film examples with a similar feel.