"Hast right" is a somewhat archaic phrase meaning "have the correct or proper thing". There are several synonyms that can be used to convey the same meaning. These include "have the truth", "have the answer", "have the solution", "be correct", "be accurate", "be right", "be on the mark", and "hit the nail on the head". All of these phrases convey the idea that something is true or correct, and that the speaker is confident in their assertion. Whether in academic discussions, legal proceedings, or debates with friends, having the right word or phrase to express oneself can be very helpful.