look up any word, like blumpkin:
 
1.
Opposite sex friends that are great to chill with Monday through Thursday but once the weekend comes it's time to go MIA. Friday will typically bring a ton of excuses or other more important things will pop up excusing them from the whole weekend. Once Monday rolls around, things return to normal and you're besties again. Could be considered an insult or a great arrangement depending on your status.
Girl 1: Are you going to his house this weekend?
Girl 2: Nah, girl, we're just weekday friends.
by Fred Flinstone 2010 March 27, 2010
 
2.
Someone you won't waste a weekend day on, guy or girl.
I don't answer John's/Jill's call from Friday night through Monday morning. They're ok for a weekday friend, but I wouldn't waste a weekend on them.
by Davywankenobi April 06, 2009