Main Entry: de·re·ism Pronunciation: 'dE-rE-"iz-&m, 'dA-rA-; dE-'rE-iz-&m, dA-'rA- Function: noun : thinking directed away from realityand not following ordinary rules of logic —de·re·is·tic/"dE-(")rE-'is-tik, "dA-(")rA-/adjective —de·re·is·ti·cal·ly/-ti-k(&-)lE/adverb