The opposite of "entertain." To make others bored and unamused.
Ms. Mullen sure knows how to untertain her students.
entertainment that fails to entertain
"Steps into Summer" is untertainment at its very finest, and will be warmly welcomed by those who watch TV with a shotgun in their mouth, trying to pluck up the courage.
(as quoted from TV critic Charlie Brooker)
–adjective
Unamusing; not entertaining.
As expected, my latest attempt at online dating was profoundly untertaining. Internyet!