expression, ichidan verb
feel like an idiot; make a fool of oneself
Used when someone ends up looking foolish or suffering a loss because of a mistake, naivety, or being taken advantage of. Often implies a sense of regret or self-deprecation.
あんな話を信じて、馬鹿を見た。
I believed a story like that and ended up looking like an idiot.
彼に金を貸したら馬
If you lend him money, you'll be the one who ends up a fool.