adjective, fat·ti·er, fat·ti·est.

consisting of, containing, or resembling fat: fatty tissue.
Pathology. characterized by overproduction or excessive accumulation of fat.

Origin of fatty

Middle English word dating back to 1350–1400; see origin at fat, -y1
Related formsfat·ti·ly, adverbfat·ti·ness, noun



noun, plural fat·ties. Informal.

Disparaging and Offensive. a person who is overweight or obese (sometimes used as a term of address).
a large marijuana cigarette, often shared and consumed by a group, with a shape and size similar to a cigar.

Origin of fatty

1790–1800 for def.1; 2003 for def. 2; fat-y2
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for fatty

Contemporary Examples of fatty

Historical Examples of fatty

  • Well, Fatty went to bed, in one of the hay bunks, pretty soon after that.

    The Depot Master

    Joseph C. Lincoln

  • I reached the dock ha'f an hour after they did, and there was Fatty waitin' for me.

    The Depot Master

    Joseph C. Lincoln

  • They in effect accuse him of fatty degeneration of the brain.

    Ireland as It Is

    Robert John Buckley (AKA R.J.B.)

  • "Say, Fatty, you should have gone into it just to lose flesh," was Andy's dry comment.

  • My Fatty is not used to such a burden as I fear Mr. Sutherland would prove.

    David Elginbrod

    George MacDonald

British Dictionary definitions for fatty


adjective -tier or -tiest

containing, consisting of, or derived from fat
having the properties of fat; greasy; oily
(esp of tissues, organs, etc) characterized by the excessive accumulation of fat

noun plural -ties

informal a fat person
Derived Formsfattily, adverbfattiness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for fatty

late 14c., from fat + -y (2). As a name for a fat person, attested by 1797 (with -y (3)).

Online Etymology Dictionary, © 2010 Douglas Harper

fatty in Medicine




Containing or composed of fat.
Characteristic of fat; greasy.
Derived from or chemically related to fat.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.