Colloquial suffix that attaches to nouns, adjectives, and verbs to express resemblance or similarity. Functions as a na-adjective.
彼は子供みたいに無邪気だ。
He is innocent like a child.
この料理はイタリアンみたいな味がする。
This dish tastes sort of Italian.
He's just like a child.
今日は夏みたいに暑いね。
It's hot like summer today, isn't it?
It seems like it's raining.
This doll looks just like the real thing.
みたい is a casual, colloquial way to express similarity, while ように is more neutral and usable in both speech and writing.
そう and みたい both express 'looks like', but みたい is more casual and can attach to nouns directly, while そう attaches to verb/adjective stems.
foolish; stupid; ridiculous; absurd
Developed as a colloquial shortening of expressions based on 見たよう, “appearing as if seen,” especially 見たようだ. It became an adjectival expression marking resemblance or inference.