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

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 • Apr. 18, 2016

Someone suggested that he could buy the down-at-the-heels New York Yankees, weak sister of the American League, for $450,000.

From Time Magazine Archive

Today, Copland has begun writing music for the people, for as large an audience as possible, "to get rid of the idea that American music is a weak sister."

From Time Magazine Archive

Circulationwise it has remained a weak sister in her hands, trailed among Manhattan's afternoon dailies only by Field's P.M.

From Time Magazine Archive

This school of life is a difficult one at best, but when a weak sister like myself is put about three grades higher than she belongs, it is more than hard.

From The Lady of the Decoration by Little, Frances, [pseud.]