weakens
v.v. to make something less strong or to become less strong yourself. You use this when talking about physical power, health, or even an argument.
v. to reduce the strength, power, or intensity of something; to become less strong or effective. Often used to describe physical structures, biological health, or abstract concepts like resolve or evidence.
The constant rain weakens the old wooden bridge.
The new evidence significantly weakens the prosecutor's case against the defendant.
Prolonged exposure to harsh ultraviolet radiation weakens the molecular bonds of the plastic, eventually leading to visible cracks and structural failure.
The verb is both transitive and intransitive; it can take a direct object or stand alone to describe a subject losing strength.