Dic & seach: off, off on

Off (one of its meanings as an adjective): Adj-7. Started on the way; going.

• I'm off to see the president.

.. The American Heritage

off (on something):

1. incorrect in one's planning or prediction. (Typically: be ~; get ~.)
   ... I was off on my estimates a little bit.
   ... I guess I was off too much.
2. to have started on something, such as a task or a journey. (Typically: be ~; get ~.)
   ... What time should we be off on our trip? We should be off by dawn.
   ... I'm off on my diet again.
3. Slang. to get high on some kind of drug.
   ... Max likes to get off on marijuana.

... McGraw-Hill Dictionary of American Idioms and Phrasal Verbs

Cf: off on one's own

• Without a good job, it is hard to go off on one's own, to one's own work and one's own new family, whenever one feels it is time.

... Ethnicity and family therapy

• It can be hard to follow and enjoy the creative work of independent minded scientific explorers. Some are well worth it, but heading off on one's own in science is inherently hazardous. Scientific ideas normally evolve through extensive interaction with others. Independent explorers may then produce nothing but interesting isolated explorations, if that. At worst, of course, and there seem to be many, independent explorers regularly fall prey to their own fantasies, a "what if I'm right" flowering of grandiose thinking, producing work of single minded imbalance and irrelevance. Then, there are a few others.

... http://www.synapse9.com/drish.htm

• As we have seen in the previous chapter, Robert Solomon objects to the plain sex view that it cannot explain why people prefer sex with others to masterbation. The search after sex with others exacts a serious toll on one's resources. On the other hand, if it is only bodily pleasure one is after, one is better off on one's own; for sexual behavior research has shown that masterbation, rather than sexual intercourse, makes for the most intense orgasm.

.... Ethics and Sex