
Slothful
Negative Connotation
 Slothful suggests strong disapproval or criticism, it's not a neutral term. 
His slothful approach to work led to his dismissal.
 Informal Usage
 The term 'slothful' is usually regarded as informal and might not suit formal writing. 
Our guide was quite slothful, delaying the tour.
 Animal Metaphor
 'Slothful' comes from 'sloth,' a slow-moving animal; it paints a vivid image of inactivity. 
They lounged on the beach, slothful as the day was long.