i-adjective
auspicious; happy; worthy of celebration
Polite form of めでたい. Used for occasions, events, or outcomes that are joyful and call for congratulations.
See also: めでたい
Your marriage is truly a happy occasion, isn't it?
新年明けましておめでたい気持ちでいっぱいです。
I'm filled with a celebratory feeling at the start of the new year.
i-adjective
naive; gullible; simple-minded
Often used sarcastically or affectionately to describe someone who is overly optimistic, trusting, or lacking in worldly wisdom. The polite prefix お adds a teasing or ironic tone.
彼は誰の言うことも信じる、おめでたい人だ。
He's a naive person who believes anything anyone says.
そんな話を真に受けるなんて、おめでたいね。
You're so gullible to take that story seriously.