A propensity is a natural tendency to behave in a certain way. We all have propensities — things we tend to do. Dogs have a propensity to bark, and many people have a propensity for getting annoyed by it.

If you have a propensity for something, then it's something that comes naturally to you or something you just do a lot. Some people have a propensity to laugh. Other people have a propensity for making others laugh, or for being generous, or for getting angry. It's hard to change your propensities. Sometimes a propensity is a bad thing, as in a criminal with a propensity for theft or murder.

Definitions of propensity

n a natural inclination

leaning, proclivity
Type of:
disposition, inclination, tendency
an attitude of mind especially one that favors one alternative over others

n an inclination to do something

leaning, tendency
Type of:
that toward which you are inclined to feel a liking

n a disposition to behave in a certain way

“the propensity of disease to spread”
Type of:
a natural or acquired habit or characteristic tendency in a person or thing