1.
yay!, hooray!, I did it!
An exclamation of joy or triumph when something good happens or a goal is achieved.
やった！合格した！
Yay! I passed!
Derived from the past tense of やる (to do). Used independently as an exclamation of success or joy.
Often elongated for emphasis: やったー！ The longer the vowel, the more excitement is expressed.
Used by all genders and ages. One of the most common exclamations of happiness in spoken Japanese.
Contrast: しまった (oh no!) expresses dismay over a mistake — the opposite emotional reaction.