Dictionary.com
Thesaurus.com
Synonyms

unsubstantiated

American  
[uhn-suhb-stan-shee-ey-tid] / ˌʌn səbˈstæn ʃiˌeɪ tɪd /

adjective

  1. not substantiated; unproved or unverified.

    unsubstantiated allegations.

  2. being without form or substance.

unsubstantiated British  
/ ˌʌnsəbˈstænʃɪˌeɪtɪd /

adjective

  1. not established as valid or genuine

    unsubstantiated allegations
"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 unsubstantiated

First recorded in 1765–75; un- 1 + substantiate + -ed 2

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.