Happy Father's Day Message - What is a dadism? A dadism is a typical saying, phrase, quote, line, or snippet of worldy life advice that a dad, daddy, or father would say. Often, these dad quotations are funny, amusing, or humourous. Dadisms are usually fondly remembered for a lifetime. Dadism items make great gifts for Father's Day, Dad's birthday gifts, Christmas gifts for fathers, or holiday gifts for dad.