the last of a succession of irritations, incidents, remarks, etc., that leads to a loss of patience, a disaster, etc.: He has been late before, but this is the last straw.
Origin of last straw
First recorded in 1840–50; after the proverb “It is the last straw that breaks the camel's back”
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for last straw
the last straw the final irritation or problem that stretches one's endurance or patience beyond the limit
Word Origin for last straw
from the proverb, "It is the last straw that breaks the camel's back"
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