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ad. headfirst

"And even then, with his own mount stumbling and nearly pitching him headforemost at each lurch, he was forced to admire the mare's goatlike agility, for she descended into the gorge in running leaps, never setting a wrong foot."

headlong    faceforemost    headfirst    facefirst   

ex-officio    aforetime    boreholesto    clotheslines    trotter