
Slack off
Informal Usage
 Used in casual conversations, not in formal or professional settings. 
I need to stop slacking off and finish my project.
 Negative Connotation
 Implies a lack of responsibility or commitment, often seen unfavorably. 
She got fired for slacking off too often at work.
 Not Always Laziness
 Can indicate taking a necessary rest or break without being lazy. 
After studying intensely, he's slacking off for a day.