Excerpt from Chesterfield County, Virginia Wills, 1774-1795. 

 

quack2

n
1.
a.  an unqualified person who claims medical knowledge or other skills
b.  (as modifier) a quack doctor
2. (Medicine) Brit, Austral, and NZ informal a doctor; physician or surgeon

vb (intr) to act in the manner of a quack

[short for quacksalver]