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).