upslack 

1. Picking up other people's slack.
2. Something that is not a lunch box.

"Man, I was upslacking for Johnny all day, and I didn't even get a thanks!"

upslack by Sierra "Oreo" C. June 30, 2005

Unslack 

To not slack; to do work in a timely and appropriate manner

Person 1 "Gabby is always on facebook these days"

Person 2 "Yeah she seriously needs to unslack!"

Unslack by Jeevs88 November 1, 2009