Describes something that feels off, contrived, or not genuine, whether in behavior, speech, appearance, or a situation. Often used for mannerisms, acting, or arrangements that lack naturalness.
His smile seemed somewhat unnatural.
不自然な沈黙が流れた。
An awkward silence fell.
その説明には不自然な点がいくつかある。
There are several unnatural points in that explanation.
The way he spoke sounded unnatural.
She showed a forced smile.
He fell silent in an unnatural way.