(physics) One of the four fundamental forces that is associated with nuclear decay. Its gauge bosons are the W⁺, W⁻ and Z⁰ particles.

describing the weak nuclear force

A person of weak or even sickly physical constitution / (figuratively) A person of weak character, lacking in courage and/or moral strength.

weak, either physically, morally or mentally

comparative form of weak: more weak / (logic) Said of one proposition with respect to another one: that the latter entails the former, but the former does not entail the latter.

(physics) The fundamental interaction responsible for the weak nuclear force.

(intransitive, idiomatic, informal) To fail to accomplish an accomplishable task or to make an attempt at less than maximum effort; to "half-ass" or "fake the funk".

Reduced; made less strong.

simple past tense and past participle of weaken

superlative form of weak: most weak