シャキーン : shakiin | define meaning
- (Internet Slang) Used to state that one has risen up to a challenge and surmounted it: I did it!; Take that!
Originally from 2ch. Cognate to the standard Japanese expression シャッキリ shakkiri or シャキッ shakki' "firm; resolute; straight; crisp".
Online, the expression is represented by the following emoji: (`･ω･´).