adjective, might·i·er, might·i·est.

having, characterized by, or showing superior power or strength: mighty rulers.
of great size; huge: a mighty oak.
great in amount, extent, degree, or importance; exceptional: a mighty accomplishment.


Informal. very; extremely: I'm mighty pleased.


(used with a plural verb) mighty persons collectively (usually preceded by the): the rich and the mighty.

Origin of mighty

before 900; Middle English; Old English mihtig. See might2, -y1
Related formsmight·i·ness, nouno·ver·might·y, adjectivequa·si-might·y, adjective

Synonyms for mighty

1. strong, puissant. See powerful. 2. immense, enormous, tremendous, sizable.

Antonyms for mighty

1. feeble. 2. small.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for mightiness

Historical Examples of mightiness

  • His high and mightiness had the whole story of the accident from some tattle-tale.

  • He could not appreciate—no man can—the mightiness of female cunning.

  • They are at my house, your Mightiness; send some one with me, and I will give them up.

  • An attempt was made to induce us to remain at a respectful distance from his mightiness.


    A. W. Kinglake

  • The mightiness of the sea, like the mightiness of the mountain, draws mankind.

    A Floating Home

    Cyril Ionides

British Dictionary definitions for mightiness


adjective mightier or mightiest

  1. having or indicating might; powerful or strong
  2. (as collective noun; preceded by the)the mighty
very large; vast
very great in extent, importance, etc


informal, mainly US and Canadian (intensifier)he was mighty tired
Derived Formsmightiness, 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 mightiness

Old English mihtinesse; see mighty + -ness.



Old English mihtig, earlier mæhtig, from miht (see might (n.)). Cf. Old Frisian mechtig, Old Saxon mahtig, Dutch machtig, German mächtig. As an adverb, it is attested from c.1300, though now considered colloquial.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with mightiness


see high and mighty.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.