Top Definition
When a sister-biological or other-does not meet your expectations; lets you down; disappoints you.
My sister was supposed to meet me at 8:30 p.m. She was an hour late. That's sisappointing!
by Larisa Terkeltaub April 30, 2008
5 Words related to sisappointing

Free Daily Email

Type your email address below to get our free Urban Word of the Day every morning!

Emails are sent from daily@urbandictionary.com. We'll never spam you.

×