Over with
What is the meaning of the phrase "when its over with"? "its" in the phrase means "it is" or smth else?

Question

Answer

Note that there is a mistake in your phrase. The word 'its' is wrong.

It should be '..when it's over with'....

The apostrophe '  tells you that the word is a contraction, in this case the contraction of 'it is'. The word 'its' is a possessive - the neutral form of 'his' or 'her'.

Answer

Yes, its = it is in this sentence.  Over with = finished.  You could also say "finished with".