noun / adjective
quack
KWAK/kwæk/
A person falsely claiming medical expertise, or something based on such claims.
The quack sells ordinary water as medicine.

Etymology
The Dutch word meant a “hawker of salve,” combining noisy boasting with selling ointment. Its shortened form became a label for someone fraudulently claiming medical skill.
In context
Later, find some excuse and get rid of that quack Doctor Jiang who sold the fake medicine.
More examples
- The advertisement promoted a quack cure.
- Patients lost money to the medical quack.
- The investigation exposed his quack remedies.
Forms
quack · quacks
quackery noun — false or fraudulent medical practice