* Formal: "Despite his impressive intellect, he has a proclivity for making impulsive decisions."
* Informal: "My dog has a proclivity for chewing on shoes, no matter how many toys I buy him."
* Figurative: "The artist's work displayed a proclivity for bold colors and abstract shapes, setting her apart from her contemporaries."
Proclivity implies a natural tendency or inclination towards something, often something that might not be entirely positive.