Does off mean - "about to leave"
and out mean - " being out"
NOT A TEACHER
(1) We non-teachers are not allowed to give answers unless we are pretty (almost)
sure that we are correct. So I shall not answer your question, for I am not confident
enough to do so. Let's wait for a teacher's answer.
(2) All I can is to give some more examples:
(a) Where's the boss? Oh, he's
out to lunch. ( = He's having lunch)
(b) It's 5 p.m. and Friday. Well, I'm
off for the weekend now. (= absent for two days)
(c) Mona is so excited. The latest fall fashions are now
out. (available to be seen and bought.)
(d) At the horse races, the announcer tells the people: And they're
off! [The horses
have just started to race.]