Shannaro

I took to research mode and I stumbled upon a blog post by Chie Nakamura, the voice actress for Sakura. She actually directly addresses the meaning of shannarou. she asked the director for the meaning and he said to think of it just like konnyarou. some of you may know that this is a contraction of kono yarou, which means 'you bastard' or whatever.
I had come across another fan theory somewhere on google groups (by native japanese fans) that shannarou was a further contraction of yossha (right!) and konnyarou. that makes a lot of sense to me.

A word Sakura from Naruto always shouts out when she's pissed or extremely excited. Could be used as "Alright, damnit!" or "F*ck yeah!"

This is a Japanese slang that does not get used in everyday language but is instead (very rarely) found in manga/anime. It is a corruption of joudan ja nai yo (冗談じゃないよ) which is a colloquial term literally meaning "this is not a joke" and can be loosely interpreted as: "stop kidding around", "don't fool yourself", "stop messing around", "you got to be kidding me", "yeah, right".

A character by the name of Sakura Haruno (春野 サクラ) in Naruto uses this a lot and many people attribute the usage of this term to the manga series. Since the word is corrupted (noted with personal accentuation), so has the meaning within certain contexts in Naruto, which defines or embodies an emotion or expression of an adrenaline rush or great excitement: "hell yeah" and "f~ yeah" is a common fansub translation.

It is commonly mistranslated as "what the f~" or "hell no" because the term was never used in that manner (given the context of a situation) and was never used as a pejorative (a handful of fansubs have taken this term to the extreme)