How To Study English

today, i came across the sentece below, when i was reading a study book for university entrance examination.

"what are you about?"

i didn't understand at all.
the word "about" has roles as a preposition and an adverb, i knew.
undoutedly, the word used in the sentence above plays a role as a preposition.
to my knowledge, the meaning of it as a preposition is

"on the subject of sb/sth; in connection with sb/sth"
(e.g There’s nothing you can do about it now.)
or
"used to describe the purpose or an aspect of sth"
(e.g Movies are all about making money these days)

i thought that "about" in the topic sentence has neither the former nor the latter.

yes. it bothered me very much.
needless to say, i refered to a dictionary, of course, english-english dictionary. and i found.

in addition to the above, the dictionary says
"busy with sth; doing sth"
that explains a lot.
in the dictionary, the example sentence is "And while you’re about it ... (= while you’re doing that)".
i got it now.

after all, the sentence "what are you about?" means
approximately "what are you doing?".

that is the reason why the person who was asked the question replied "nothing special."

i see. now it makes sense, though i got tired.