Wiktionary
a. Not theatrical; mundane; not staged.
WordNet
adj. not suited to or characteristic of the stage or theater; "a well-written but untheatrical play"; "an untheatrical personality" [ant: theatrical]
Usage examples of "untheatrical".
This phrase is probably unintelligible to the untheatrical portion of the community, which may now be said to be all the world except the actors.
Is it not true, that there is in the very substance of the English mind, that which naturally predisposes us to sympathy with the Drama, and this though we are perhaps the most untheatrical of all people?
He made curious, untheatrical gestures that seemed to have some kind of significance.
Finally the untheatrical construction is entirely un-Gogolian, and in the deliberate discarding of all tricks and contrivances at scenic effect Ostrovsky from the outset attains his best.