Not flammable, especially not readily ignited and not rapidly burned.(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 "nonflammable" in a sentence
"Note - you would think Mr. Robinson would want his current soldiers to have the very best, safest - nonflammable equipment to mount a military operation."
"It is a colorless, nonflammable gas which has an odor of freshly-cut grass."
"The MSHA said Massey failed to spread enough nonflammable crushed limestone on surfaces to neutralize the coal dust."