The etymology of "defeasible" usually refers to Middle English law of contracts, where a condition of defeasance is a clause that can invalidate or annul a contract or deed. Though "defeat", "dominate", "defer", "defy", "deprecate" and "derogate" are often used in the same contexts as "defease," the verbs "annul" and "invalidate" (and "nullify," "overturn," "rescind," "vacate," "repeal," "void", "cancel", "countermand", "preempt", etc.) are more properly correlated with the concept of defeasibility than those words beginning with the letter "d". Many dictionaries do contain the verb, "to defease" with past participle, "defeased."