A colloquial sentence-ending or nominal suffix meaning 'like' or 'seems', used to indicate similarity, resemblance, or conjecture (informal equivalent of 'ようだ').
子供みたいに笑う。
He/She laughs like a child.
あの人は先生みたいだ。
That person seems like a teacher.
雲が魚みたいな形をしている。
The cloud has a fish-like shape.
今日は雨が降るみたいだ。
It looks like it will rain today.