'Weakening' definitions:

Definition of 'weakening'

(from WordNet)
adjective
Causing debilitation [syn: debilitative, enervating, enfeebling, weakening]
adjective
Moderating by making pain or sorrow weaker
noun
Becoming weaker [ant: strengthening]
noun
The act of reducing the strength of something [ant: strengthening]

Definition of 'Weakening'

From: GCIDE
  • Weaken \Weak"en\, v. t. [imp. & p. p. Weakened; p. pr. & vb. n. Weakening.] [1913 Webster]
  • 1. To make weak; to lessen the strength of; to deprive of strength; to debilitate; to enfeeble; to enervate; as, to weaken the body or the mind; to weaken the hands of a magistrate; to weaken the force of an objection or an argument. [1913 Webster]
  • Their hands shall be weakened from the work, that it be not done. --Neh. vi. 9. [1913 Webster]
  • 2. To reduce in quality, strength, or spirit; as, to weaken tea; to weaken any solution or decoction. [1913 Webster]

Definition of 'weakening'

From: GCIDE
  • moderating \moderating\ adj. lessening in intensity or strength. Opposite of intensifying. [Narrower terms: tempering; weakening] [WordNet 1.5]