General trouble:
* Difficulty
* Problem
* Issue
* Hardship
* Dilemma
* Predicament
* Quandary
Trouble caused by someone:
* Mischief
* Chaos
* Disorder
* Agitation
* Discord
Trouble with the law:
* Legal issues
* Conviction
* Charges
* Misconduct
Trouble as a feeling:
* Anxiety
* Worries
* Stress
* Fear
* Concern
It's important to consider the specific situation you're referring to when choosing the best synonym for "trouble."