malpractitioner Definition

1a. law.
Improper, careless, illegal or unethical professional conduct, eg medical treatment which shows a lack of reasonable skill or care, the misuse of a position of trust, etc;
Thesaurus: negligence, neglect, carelessness, misconduct, mismanagement, transgression, misbehaviour.
1b. law.
An example or instance of this. See also negligence.
2. Any wrong or illegal act.