Following an endorsement by former Ku Klux Klan leader David Duke, Donald Trump surprised many by refusing to repudiate the white supremacist—and perplexed many others by appearing to not know who Duke is, given that Duke has been prominent in politics for decades and ran for president in 1988. Press coverage and headlines noted Trump’s initial refusal to disavow the endorsement, and finally Trump tweeted: “I disavow.”
Disavow means “to refuse to acknowledge or accept” or “to deny responsibility for” and is a synonym of repudiate. It’s the negative form of avow, which means “to declare or state (something) in an open and public way”; it came to English from a French word and ultimately from the Latin root advocare, meaning “to call” or “to summon.” The literal etymological meaning of disavow is “to refuse to summon.” Another English descendant is advocate.
It might seem that disavow is related to vow (“a solemn promise”), but it isn’t: the “-vow” part of disavow comes from the Latin word vox meaning “voice.”