Repent, OT form is Tshuva - meaning "to turn back", "to return".
Repent, NT form is metanoeō meaning literally, "to change your mind".

However, in search of an accurate definition, it would be insufficient to stop there. In order to get a fuller understanding of it's meaning you must look at it's real-world usage. In scripture we see that Esau did NOT attain repentance even though He sought it with tears! Obviously, in practical usage, the word repentance does not mean to feel sorry, regret, or remorse. Esau felt great sorrow, regret and remorse. However, he was NOT able to repent.

I get my definition by the careful consideration of two things. 1. By studying the listed definition in the original Hebrew and Greek, AND 2. By studying it's practical usage in scripture. Coupling those two factors in the equation, there is no other logical conclusion but to say that the word "repent", as used in scripture, means "to change". Obviously that includes changing your mind, causing you "to turn", thus in most circumstances leads to changing your life (at least in the NT sense).

Where do you get your definition from?