weak sister

Noun

 * 1)  A person who is cowardly or indecisive.
 * 2) * 1964, "Political Thriller" (film review of Seven Days in May), Time, Feb. 21:
 * "Your course of action this past year has bordered on criminal negligence," he barks to the man whose job he means to take. "You're a weak sister, Mr. President."
 * 1)  A person or thing which is the least robust or least dependable member of a group.

Synonyms

 * sick man