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Webster 1828 Edition

ppr.

Depriving of strength, force or vigor; weakening; enfeebling.

enervating

present participle of enervate
- 1914, Louis Joseph Vance, Nobody, chapter III:
  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.