General terms:
* Motivation: This is the most direct synonym, meaning the drive or energy that encourages people to act.
* Stimulus: Something that encourages or prompts a particular action or feeling.
* Influence: The power to affect someone's thoughts or actions.
* Encouragement: Words or actions that give someone support or confidence.
* Empowerment: Giving people the power or confidence to act independently.
* Guiding light: A metaphorical term for someone who shines a path for others.
* Role model: Someone who inspires by setting a positive example.
More specific terms:
* Muse: Someone who inspires artistic creation.
* Catalyst: Something that triggers a process or event.
* Beacon: A guiding light that attracts attention and provides hope.
* Pioneer: Someone who breaks new ground and inspires others to follow.
* Visionary: Someone with a clear and exciting vision of the future that inspires others.
The best word for you will depend on the specific context.