にやにや

にやにや
adverb, verb (suru)
grinning, smirking
1. grinning, smirking
Smiling in a knowing, often mischievous or self-satisfied way.
(なに)をにやにやしているの?
What are you smirking about?
にやにやしながら(はな)している。
He's talking with a grin on his face.
にやにや(わら)いが気持(きも)(わる)い。
That smirk is creepy.

にやにや is a mimetic word describing a sly, knowing, or self-satisfied smile.

USAGE:

  • にやにやする: to grin, to smirk
  • にやにや(わら)う: to smirk
  • にやにやしながら: while smirking

NUANCE:
Often carries negative or suspicious connotations - the person seems to know something others don't, or appears self-satisfied in an off-putting way.

CONTRAST WITH SIMILAR WORDS:

  • にこにこ: smiling pleasantly, warmly (positive)
  • にたにた: grinning unpleasantly (more negative than にやにや)
  • にっこり: giving a single bright smile (positive, momentary)
  • にんまり: grinning with satisfaction (can be positive or negative)

EXAMPLE CONTEXT:
(なに)をにやにやしているの? is often said when someone's smirk seems suspicious or annoying.