croaker
noun
1
a doctor, especially a company doctor. Sometimes abbreviated to 'croak' UK, 1879.
2
a doctor who provides narcotics for an addict. A specialisation of the previous sense US, 1978.
3
a habitual complainer. In C19 US use, but now obsolete there AUSTRALIA, 1882.
4
a dying person, or one who has just died. From CROAK (to die) UK, 1873