An optimist

gravediggerWhich is correct?
A. I am an optimist. (noun)
B. I am optimist. (adjective)

Only the first. You need this for the adjective:

I am optimistic.

CJ

Now, would you please tell me what the difference is between these two sentences?

I am an optimist.

I am optimistic.

Thank you...

GRAVEDIGGER

The grammar is different -- noun vs. adjective.
The meaning is the same.

In actual practice, the noun form is usually complete as it stands. It says that I generally have an optimistic outlook on everything in general.

The adjective form, however, is typically amplified by saying what I am optimistic about:

I am optimistic about my chances of winning the race.