General:
* Linger
* Dawdle
* Tarry
* Hang around
* Idle
* Dally
* Stroll
* Saunter
* Wander
* Amble
More specific:
* Hang back: To delay or hesitate to move forward.
* Lag behind: To fall behind in speed or progress.
* Snooze: To sleep lightly or briefly.
* Procrastinate: To delay or postpone something.
* Wallow: To indulge in something excessively, especially something pleasurable or negative.
Negative connotations:
* Shirk: To avoid work or responsibility.
* Skulk: To move about secretly or stealthily, often with evil intent.
* Hang out: To spend time idly or without purpose, often in a place where one is not supposed to be.
The best synonym for "loiter" will depend on the specific situation and the desired tone.