～っぽい・~ppoi/

When we criticize something or while taking about the quality of something at that time "~ppoi" sentence pattern is used.
There is a negative shade to this sentence pattern.

Either i-adjective or noun is used before this phrase.

In case you use i-adjectives then just remove "i" and add "ppoi" to it.
In case of nouns directly add the phrase to it.

Some examples have been provided to you below:

この小学生は大人っぽい。（＝大人みたいだ）
That child (primary school student)  acts very adult like.

この料理は油っぽくていやだ。（＝油が多い感じがして）
I don't llike this dish. It is too greasy.