A colloquial adjectival suffix meaning '-ish' or '-like', indicating appearance, tendency, or a characteristic (e.g., childish, cheap-looking).
彼は子供っぽいところがまだある。
He still has some childish tendencies.
このバッグは安っぽい素材で作られている。
This bag is made of cheap-looking material.
忘れっぽい人はメモを取るといい。
People who tend to forget should take notes.
彼女、疲れてるっぽいね。
She seems tired, doesn't she?