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look over

Look over is a phrasal verb.

When you look over something or someone you quickly examine it or them.

For example:-

I asked my teacher to look over what I had written.

Overlook is a verb.

When you overlook someone or something you fail to notice or consider it or them.:

For example:

I think my teacher overlooked some of my mistakes.

!Look over is two separate words, overlook is one word.