meaning of the phrase "by inclination"

[Sophie]

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.
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On earth there is nothing great but man, in man there is nothing great but mind.

[Molly]

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

[Maryann]

Being ambitious is not my trait of character.

[Jamie (K)]

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