Simple past tense and past participle of thicken.(verb)
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Use "thickened" in a sentence
""That's what I call thickened truth," said the American, looking solemnly round."
"It does seem unlikely that a Habermasian cosmopolitianism, no matter how supplemented and thickened, is going to be able to open itself to forms of ethos and character that come from religious traditions."
"The name thickened to a sob as he repeated it, and then suddenly he rose and cried in an awful voice, "Oh, I'm a fool!"