Some words exist and some would need some creative translating.
First of all the words that exist:
vaz = storm
gorat = to charge, to give the command Charge! would be Gori!
az = blade
lorrat = to blink, again this is the infinitive so depending on the use it would have to be conjugated.
Now there is no word outright for assassin that we know of. If you want to just say "a killer" it would be addrivak. For something like a contract killer you could perhaps say Addrivak athjerari which would be something like "A trading killer". If you want to convey the word assassin as someone who kills in secret then you could perhaps say addrivak torga essheyi which literally means "killer under a roof" but more generally means "secret killer" since the Dothraki believe that things should be done out in the open so things that are done under a roof are secretive.
