Would you please tell me between act and action?

They are similar in many ways, and can often be interchanged. However, here's a couple of brief comments.

act Something that is done. Suggests that the 'doing' is completed. eg this murder is a criminal act.

action Usually focuses more on the process of 'doing' the act'. eg this movie is very exciting, it is full of action.

Best wishes, Clive
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I believe ACT is like Clive said, a completed deed. I think action is usually more like part of a deed. For example, a kind ACT may require several ACTIONS. Describing the thing in it's entirety is usually ACT and describing how one did it is usually ACTIONS.

I walked the lady across the street, holding her arm and carrying her bag. Joe said, "your actions there were very kind. Indeed it was a kind act."

Maybe it's a stupid sentence, but I think that's the meaning.
act is a verb or an abstract noun, depending on its context.

action is an abstract noun.