General:
* Inclination
* Propensity
* Disposition
* Proneness
* Liability
* Habit
* Bent
* Leanings
* Drift
More specific:
* For actions/behavior:
* Habit
* Practice
* Predilection
* Proclivity
* Inclination
* For thoughts/feelings:
* Bias
* Prejudice
* Leaning
* Slant
* For situations/events:
* Trend
* Pattern
* Drift
* Current
* For potential:
* Liability
* Vulnerability
* Susceptibility
The best synonym to use will depend on the specific context of your sentence.