Carried out without the benefit of wise counsel or careful deliberation, or carried out with unwise counsel
without careful prior deliberation or counsel; "ill-advised efforts"; "it would be ill-advised to accept the offer"; "took the unadvised measure of going public with the accusations"; "ill-advised efforts
If you describe something that someone does as ill-advised, you mean that it is not sensible or wise. They would be ill-advised to do this. not sensible or not wise and likely to cause problems in the future ill-advised to do sth