Casual interjection or adjectival noun used to express approval, satisfaction, or that something is good. Often used in informal conversation, similar to English 'good' or 'nice'.
from English good
このアイデア、グーだね。
This idea is good, isn't it?
This ramen's flavor is really great.
The test result was good.
グー！その調子で頑張って。
Good! Keep it up.
"How was the test?" "Great!"
fist bump
just right!; excellent!; perfect!
Loanword from English 'good', adapted into Japanese as グー. The long vowel is represented by the prolonged sound mark (ー).