worrier

English edit

worry +‎ -er

worrier (plural worriers)

A person who worries a great deal, especially unnecessarily.
You are such a worrier! I'm sure everything will turn out all right.
A person who causes worry in others.
An animal that seizes or shakes another by the throat.
- 1886, New Zealand. Parliament, Parliamentary Debates, volume 54, page 401:
  The person owning a dog which had destroyed sheep could be made to pay for the damage; but the Court should also have an undoubted power to order incurable sheep-worriers to be destroyed.

(one who worries a great deal): bundle of nerves, worrywart; see also Thesaurus:worrier
(one who causes worry in others):

A person who worries a great deal, especially unnecessarily

A person who causes worry in others