Made or designed to be worn without a belt: an unbelted jacket. (adjective)
Not having or using a seat belt: tests of unbelted dummies at various impact speeds. (adjective)
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 "unbelted" in a sentence
"Perhaps more along the lines of the .375 Ruger and .338 Federal that seem to offer balanced performance in unbelted cases."
"Front airbags original purpose was to protect "unbelted" occupants, yet they added over $1,000 to the cost of the vehicle when introduced."
"Some 75% involved an unbelted rider; 84% an unhelmeted rider; 52% high speeds and sharp turns; and 29% drugs or alcohol."