Fortunately for the world, the weak sister and her theories do not rule.
And later on, when I knew her, she was a weak sister whom I tried to help.
She is the limit beyond which no one must go, under pain of such displeasure as the weak sister can show.
Unsatisfactory in her home, the weak sister does not do much better in society.
He waz rather a weak sister, and alwus rode sideways on a side-saddle.
An unreliable person, esp a male (1857+)