ichidan verb, intransitive verb
to be effeminate; to be a fop
Describes a man who is overly concerned with his appearance, acting in a way considered unmanly or dandyish. Somewhat dated and may carry a negative or mocking tone.
彼はいつも鏡を見ていて、少しにやけている。
He's always looking in the mirror and is a bit of a fop.
ichidan verb, intransitive verb
Colloquial use, often describing a silly or self-satisfied grin. Related to the mimetic word にやにや (grinning).
See also: にやにや
彼は何かいいことでもあったのか、にやけている。
He's grinning as if something good happened.
いたずらを考えているとき、彼はにやける。
He grins when he's thinking of a prank.