weak sister

noun, Informal.
1.
a vacillating person; coward.
2.
a part or element that undermines the whole of something; a weak link.
Origin
1855-60
Examples from the web for weak sister
  • However, all of the daughters became rather strong and domineering themselves, with not a weak sister in the lot.
  • Being a weak sister she will readily yield te our persuasion.
  • Even riparian protection is a weak sister to this new context.
British Dictionary definitions for weak sister

weak sister

noun
1.
(US, informal) a person in a group who is regarded as weak or unreliable
Slang definitions & phrases for weak sister

weak sister

noun phrase

An unreliable person, esp a male (1857+)