na-adjective, noun
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.
彼の笑顔はどこか不自然だった。
His smile seemed somewhat unnatural.
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.