Definition of "enervating"

No enervating arts refinedTo slumber lull'd his heaven-born might;No weak indulgence warp'd thy mind,To cloud a hero's path of light.

1827, Lydia Sigourney, Poems, Grave of the Mother of Washington, page 10

I rose by candle-light, and consumed, in the intensest application, the hours which every other individual of our party wasted in enervating slumbers, from the hesternal dissipation or debauch.

1828, [Edward Bulwer-Lytton], chapter XX, in Pelham; or, The Adventures of a Gentleman. […], volume II, London: Henry Colburn, […], page 196

Turning back, then, toward the basement staircase, she began to grope her way through blinding darkness, but had taken only a few uncertain steps when, of a sudden, she stopped short and for a little stood like a stricken thing, quite motionless save that she quaked to her very marrow in the grasp of a great and enervating fear.

1914, Louis Joseph Vance, “Accessary after the Fact”, in Nobody, New York, N.Y.: George H[enry] Doran Company, published 1915, page 43