The word "weaken" is correct and usable in written English.
You can use it to refer to a decrease in strength, power, or intensity. For example, "The sun's rays weakened as the day wore on."
MND progressively weakens the muscles until the sufferer cannot do anything by himself.
Even when I ended up bleeding heavily after a skateboarding accident – chemotherapy weakens the scarring process – my friend found it amusing, which made it seem less serious.
Ryan says that this somehow weakens America's allies and emboldens its enemies.
Anything that weakens the Greek economy and undermines democracy could strengthen the Greek neo-Nazi movement and do real harm to economically vulnerable people in Greece.
As soon as Die Linke weakens its present anti-Nato position, the SPD would probably enter into a coalition at federal level.
Pete Reeve, the Ukip local government spokesman, said: "It weakens the already tenuous link between the MP and his or her constituents.
Bottrill had the auto-immune system deficiency Myasthenia Gravis, an illness that weakens the muscles.
The rise of the anti-big business, populist rightwing parties also simultaneously weakens both the mainstream leftwing and the corporate sector's ability to shape policies.
First, it makes Japanese exporters more competitive and thus weakens the position of rival exporting nations.
Hunger has, in turn, made the impact of the AIDS crisis in Africa far worse lack of nourishment further weakens the immune systems of those infected.But if there is broad agreement on the scale, nature and urgency of the problems, finding a consensus on how to tackle them is more difficult.
In 1912 an exhaustive treatise on the subject, "The Soldier's Foot and The Military Shoe" by Edmund Munson, an American general, warned against wearing thick soles and stressed that a shoe should not support the arch, as that only weakens the foot muscles.
