unitasking 

To do one thing at a time. The opposite of multitasking.

Mike loved unitasking despite never meeting his targets because of it. Each time someone talked to him he had to switch off his computer in case he would multitask by accident.

unitasking by pojdnc May 31, 2010

Unitasking 

What mothers, sales clerks and admin assistants have absolutely no possibility of ever trying. Ever.

Emma: Can you hold on a sec please, I'm trying to concentrate on this email to the president you asked me to compose.

Emma's boss: What? You think I pay you to sit around unitasking?!? I want all eight of these things done right now! Yesterday, in fact!

Unitasking by Veranda Collingwood January 13, 2013