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mothball

American  
[mawth-bawl, moth-] / ˈmɔθˌbɔl, ˈmɒθ- /

noun

  1. a small ball of naphthalene or sometimes of camphor for placing in closets or other storage areas to repel moths from clothing, blankets, etc.

verb (used with object)

  1. to put into storage or reserve; inactivate.

adjective

  1. inactive; unused; stored away.

    a mothball fleet.

idioms

  1. in mothballs,

    1. in disuse or in storage, especially with reference to standby equipment.

    2. (of ideas) dismissed as unworthy of further deliberation.

mothball British  
/ ˈmɒθˌbɔːl /

noun

  1. Also called: camphor ball.  a small ball of camphor or naphthalene used to repel clothes moths in stored clothing, blankets, etc

  2. to postpone work on (a project, activity, etc)

"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

verb

  1. to prepare (a ship, aircraft, etc) for a long period of storage by sealing all openings with plastic to prevent corrosion

  2. to take (a factory, plant, etc) out of operation but maintain it so that it can be used in the future

  3. to postpone work on (a project, activity, etc)

"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

Etymology

Origin of mothball

First recorded in 1905–10; moth + ball 1

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

“It literally goes into mothball mode,” said Len Kientz, Evonik’s director of energy management in North America.

From The Wall Street Journal • Feb. 10, 2026

Manolo Blahnik did a shoehorn, Isaac Mizrahi designed a mothball that’s a cube, so it didn’t roll, and I ran it at 30 pages with the title “Hey, Target: How About This?”

From New York Times • Jul. 1, 2023

Peter Done, CEO of Manchester-based HR specialists Peninsula, isn't ready to mothball his suit just yet.

From BBC • Oct. 4, 2022

Briant has had to mothball the giant inflatable walk-through colon she used to send to events in tribal areas and gatherings of agricultural workers throughout Washington State.

From Scientific American • Nov. 18, 2021

For example, many combat ships are being returned to active duty from the "mothball fleet" and many others can be put into service on very short notice.

From State of the Union Address by Truman, Harry S.

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

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