Idiom from Latin: idioma, special property is an expression, word or phrase that has a figurative meaning; this is separate from the literal meaning or definition of the words of which it is made. Word-group becomes an idiomatic expression. The words develop a specialized meaning as an entity, as an idiom. When a speaker uses an idiom, the listener might mistake its actual meaning, if he or she has not heard this figure of speech before. In English the expression to go round the bend, would mean to go insane.