Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
☆ Slang a gradual working up or show of anger: often in the phrase
Used by arrangement with John Wiley & Sons, Inc.
noun SlangThe American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
A gradually increasing sense or show of anger: did a slow burn while waiting three hours in the doctor's office.
slow burn - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Slowly increasing anger. It is often put as do a slow burn, meaning “gradually grow angrier,” as in I did a slow burn when he kept me waiting for three hours. The burn in this idiom comes from burn up in the sense of “make furious.” The term was first cited in 1938 and was closely associated with comedian Edgar Kennedy.