Second-person singular present simple form of turn(verb)
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Use "turnest" in a sentence
"This is the same air that heard thee say it; and after all thou turnest round and hast been caught recasting thy letter to this effect, "I will no longer be my daughter's murderer.""
"Why turnest thou thy cheek away, and hast no welcome for my glad news?"
"Relying on the truce, which saves thy life, thou turnest boaster."