Putting a hyphen or space, does change the keyword?

[abhirupb]

Does putting a hyphen or a space can change the original keyword? We are having an issue here. If we put the two words together its grammatically incorrect but gets a lot of hits. Can we use hyphen or a space here?

[ksmith29]

I many cases people use intentionally incorrect words, why? Because they gets targeted traffic. So, don't bother which one to choose. Choose that one which one your audience prefer.

[richardmsmith]

I think don't anything will happen but what is the need for this use hyphen just put long tail keyword.