The definition of irresistible is something that you have to have because it is too desirable or wonderful to restrain yourself from having.(adjective)
A delicious piece of chocolate cake is an example of something that would be described as irresistible by a person who loves chocolate cake.
See irresistible in Webster's New World College Dictionary
Origin: LL irresistibilis
See irresistible in American Heritage Dictionary 4
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