verb (used with object)
Phonetics. to change (a speech sound) to an articulation requiring less effort, as from geminate to nongeminate or from stop to fricative.
verb (used without object)
1, 3. enfeeble, debilitate, enervate, undermine, sap, exhaust, deplete, lessen, diminish, lower, reduce, impair, minimize, invalidate.
1, 3. strengthen.