"no" instead of "not a"?
When is it OK to use "no" instead of "not a"? Is there a difference in meaning?
In the case of "I am no...," "s/he is no...," etc., the "no" puts a very strong emphasis on the negation. Whereas "not a" would sound like a statement of fact here, the "no" sounds defiant (which is perfect for the scene you presented)
As far as when to use it, "not a" is vastly more common. "No" here can sound hostile, depending on the situation, but if someone makes one claim, such as "No man can kill me," and you want to make it perfectly clear that you are not a man, then you can say "I am no man."
Perfekt. Das könnte ich nicht verbessern. Bin Engländer und empfehle gern Stephens Erklärung dieser Sache. Es ist aber wert zu sagen, dass das mit "no" sich poetisch anhören kann.
"No" has a slightly stronger emphasis, sounds very slightly old-fashioned and is almost always used to contradict a previous statement, implication or assumption.
"No man can kill me" (implying you, a man, cannot kill me)
"I am no man" (contradicting the previous implication)
"He's heading for that small moon."
"That's no moon." (contradicting the statement that that is a moon).
"No" negates a noun, much like "kein."
"not" negates a verb or adjective, much like "nicht."
I have no sisters. (Ich habe keine Schwestern)
I am not tired. (Ich bin nicht muede)