weak sister

American  

noun

Informal.

1. a vacillating person; coward.

2. a part or element that undermines the whole of something; a weak link.

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weak sister British  

noun

1. informal a person in a group who is regarded as weak or unreliable

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Etymology

Origin of weak sister

First recorded in 1855–60

Example Sentences

One theory goes that by talking tough, Trump is alerting the world that the United States is no longer the weak sister, if I may use an old expression, it had become under President Barack Obama.

From Washington Post

Fear is a very weak sister and, yes, they really should get rid of those brooding teenagers and maybe Travis too.

From New York Times

Some conservatives in the GOP saw Boehner as a weak sister, unwilling to fight on principle for the values expressed by the coalition of voters that had put them in office.

From US News

There’s no weak sister in conference.

From Washington Times

The N.F.L.’s player’s union long has been a labor weak sister.

From New York Times