Neutral:
* Indolent: Suggests a relaxed and inactive state.
* Lethargic: Implies a lack of energy or enthusiasm.
* Unproductive: Emphasizes the lack of output or results.
* Sluggish: Refers to slowness and lack of movement.
* Lackadaisical: Shows a lack of interest or effort.
* Unmotivated: Indicates a lack of desire to act.
* Passive: Suggests a preference for inactivity.
Negative:
* Idler: Implies someone who avoids work or responsibility.
* Slacker: A more informal term for someone who shirks their duties.
* Good-for-nothing: Conveys a strong sense of worthlessness.
* Shiftless: Indicates a lack of purpose or direction.
* Listless: Emphasizes a lack of energy and spirit.
* Slothful: Suggests a strong tendency towards laziness.
* Recalcitrant: Indicates resistance to effort or work.
Informal:
* Deadbeat: A more slang term for someone who avoids work.
* Couch potato: Used for someone who spends a lot of time watching TV.
* Bum: A derogatory term for someone who is lazy and unproductive.
The best synonym to use will depend on the specific context and the desired tone.