I am no sth / I am "not" sth.

lv0606

I am no sth / I am not a sth. (e.g. I am no coward/ I am not a
coward)
what are the differenced between them

There is no difference in the basic message. Each one is saying
that the speaker is not a coward (or whatever was said instead of \"a
coward\").

However, there is still a difference in WHEN you might hear them.
The \"not a XXXX\" version is the most common. This is what you would
normally use when you want to say you are not a XXXX.

The \"no XXXX\" is more of a denial, a strong defiance of what someone
or something has accused you of being. You might say it when someone
says directly to you \"You, sir, are a total coward!\" If you are
feeling very angry and defiant, instead of just muttering \"I'm not a
coward\" you might want to stand up tall, puff out your chest, and say
firmly \"I am no coward.\" It's also better to then go and do something
that proves your denial and leaves your accuser thoroughly convinced
that you are indeed not a XXXX.

Anyway, the basic difference is in the way you want the denial to be
taken. Is it just a straightfoward \"I'm not a XXXX\"? If so, use
\"I'm not a XXXX.\" Or is it more of a defence of an accusation, a firm
denial of something? If so, use the \"I'm no XXXX.\"