Learned borrowing from New Latin prōpensitās. By surface analysis, propense (“inclined, disposed”) +‎ -ity.

• IPA^(key): /pɹəˈpɛnsɪti/

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propensity (countable and uncountable, plural propensities)

1. An inclination, disposition, tendency, preference, or attraction.

   He has a propensity for lengthy discussions of certain favorite topics.

   • 1831, L E L, “The Last Chapter”, in Romance and Reality.  In Three Volumes.">…], volume III, London: Henry Colburn and Richard Bentley, , →OCLC, page 326:

     I must own they do dearly delight in a judgment; and sorry am I that I cannot gratify this laudable propensity by specifying some peculiar evil incurred by Mr. Delawarr's ambition, or Lady Etheringhame's vanity.

   • 1902, William James, “Lecture I”, in The Varieties of Religious Experience: A Study in Human Nature , New York, N.Y.; London: Longmans, Green, and Co. , →OCLC:

     To the psychologist the religious propensities of man must be at least as interesting as any other of the facts pertaining to his mental constitution. It would seem, therefore, that, as a psychologist, the natural thing for me would be to invite you to a descriptive survey of those religious propensities.

   • 1949, F. A. Hayek, “The Intellectuals and Socialism”, in University of Chicago Law Review, volume 16, number 3, Chicago: University of Chicago, →DOI, page 424:

     Here their peculiar propensities manifest themselves in making shibboleths of abstractions, in rationalizing and carrying to extremes certain ambitions which spring from the normal intercourse of men.

   • 1988, Douglas Adams, The Long Dark Tea-Time of the Soul, William Heinemann Ltd, page 29:

     He had a tremendous propensity for getting lost when driving.

   • 2013 May-June, Katie L. Burke, “In the News”, in American Scientist, volume 101, number 3, page 193:

     Bats host many high-profile viruses that can infect humans, including severe acute respiratory syndrome and Ebola. A recent study explored the ecological variables that may contribute to bats’ propensity to harbor such zoonotic diseases by comparing them with another order of common reservoir hosts: rodents.

• proclivity, propension, predilection, see also Thesaurus:predilection

• propense
• propend