This came up recently as mentioned in a comment:
Is it acceptable to leave hints as answers?
As can be seen there the notion "hint" is not well-defined and even if it were opinions would still be mixed. Since you look for a definitive answer, let me try to record some things that are, I believe, mostly consensus.
It is allowed to post something as an answer post that does not literally contain the answer. For example, a good description of the steps needed to solve a problem can be given in lieu of a literal answer.
It is allowed to post a partial answer.
Sloppy and and poorly crafted posts are discouraged. (Not all hints are sloppy, not all literal answers are not sloppy.)
Posts prone to be misunderstood are discouraged.
Posts should be able to stand a bit on their own. Of course it is sometimes, even often, not possible to be self-contained. Yet consider the thought-experiment that for an hour all links are broken. Would the post be interesting during that hour? If not, it does not stand on its own.
If somebody concludes that a posts does not meet these criteria, they might decide to take action against it via downvote and/or delete votes. This is also allowed.