The state of not being used or of being no longer in use.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "disuse" in a sentence
""It is probable that _disuse has been the main agent in rendering organs rudimentary_," or in other words that Lamarck was quite right -- nor does one see why if disuse is after all the main agent in rendering an organ rudimentary, use should not have been the main agent in developing it -- but let that pass."
"_disuse_ during a long series of generations, its thickness is rather an illustration of atavism still resisting the effects of long-continued disuse."
"There is such a thing as rudimen - tary organs which served functions long since fallen in disuse and now unremembered."