Dictionary / Vocabulary / 当人
とうにん
the person concerned; the person in question; the said person
JLPT N1 common word
「騙された」と言ってしまえばそれまでですが、「うまい話」に乗った当人であることは間違いありません。
If you say "I was tricked," well that's certainly so but there's no mistaking that you were the one who signed up on a "sweet deal".
当人の終始変わらない努力が最後にものを言うのである。
It is your constant efforts that count most in the end.
当人のいないところで悪口を言うべきでない。
You shouldn't speak ill of a man behind his back.