Haram

whatever that GOD/ALLAH has forbid his slaves/mankind/humans of doing in islam following the suna and quran

but in slang it means anything that's inhuman,bad,naughty.

EX : a man drinking beer is haram

: a man eating pork is haram

: a man committing murder is haram

Walahi

it means literally "ON GOD" meaning that you swear on the creator and the begining and ending of all, that is GOD that you did or did not do something or believe or believe not something .

And it could be used to resemple or represent ACCEPTANCE,DENIAL,IGNORANCE,THREATS...etc

ex: WALAHI I didn't hit you

WALAHI I slept around 10 AM TOO !

WALAHI you lying