meaning of the phrase "by inclination"

Could you please explain the meaning of the phrase “by inclination”?

For example:

I’m not by inclination a particularly ambitious man.

Thank you very much.

It’s not in my nature to be ambitious.
I’m not naturally ambitious.

Being ambitious is not my trait of character.

Remember that “inclination” means “leaning”, so we could also say someone “leans toward ambition”.