This document discusses idioms, which are combinations of words that have a figurative meaning due to common usage that is different from the literal meaning. Some examples of idioms provided are "at the eleventh hour" meaning at the last minute, "as easy as pie" meaning very easy, and "keep/stay in touch" meaning remain in contact. The document notes that many idioms originally had literal meanings not figurative ones, such as "spill the beans" coming from literally spilling beans. It concludes that idioms contradict the principle of compositionality in linguistics, which is that understanding the meaning of individual parts should allow understanding of the whole.