un·​sub ˈən-ˌsəb How to pronounce unsub (audio)
plural unsubs
US law enforcement, informal
: the unknown perpetrator of a crime
Not one but two murderous unsubs are on the loose in tonight's Criminal MindsTV Guide
Rhyme remembered the thousands of times he'd run crime scenes. Sometimes a miracle would happen. He'd be looking around and somehow ideas about the unsub would come to him. He couldn't explain how.Jeffery Deaver

Example Sentences

Recent Examples on the Web The trauma of her shooting and the pressure of her job leads to the BAU agent shooting an unsub. Alamin Yohannes, EW.com, 13 Jan. 2023 The real masterstroke is casting Zach Gilford as the prime unsub, the spiritual leader of a nationwide network of murderous acolytes. Joshua Alston, Variety, 21 Nov. 2022 Fairly quickly, the agents ruled out a foreign power as the culprit, deciding that the unsub must be a C.I.A. insider. Patrick Radden Keefe, The New Yorker, 6 June 2022

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'unsub.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


unknown (or unidentified) subject

First Known Use

1965, in the meaning defined above

Time Traveler
The first known use of unsub was in 1965

Dictionary Entries Near unsub

Cite this Entry

“Unsub.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unsub. Accessed 27 Mar. 2023.

Last Updated: - Updated example sentences
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