A friend who displays affection and kindness in a way your own sister would if she really cared about anyone but herself.
Jay was being super sisterly by supporting my decision to get an abortion.
by SBRstar October 10, 2013
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The 'love' between two sisters.

Normally sarcastic-
Y: Yup, my sister told me to jump off a cliff today..
N: Just 'sisterly love'.
by Sillie-Tits February 12, 2018
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