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early 15c., from Middle French debilite (Modern French débilité) or directly from Latin debilitatem (nominative debilitas) "a laming, crippling, weakening," from debilis "lame, disabled, crippled," figuratively "weak, helpless," from de- "from, away" (see de-) + -bilis "strength," from PIE root *bel- (see Bolshevik).
debility de·bil·i·ty (dĭ-bĭl'ĭ-tē)
The state of being weak or feeble; infirmity.