减弱 (jiǎn ruò): 弱体化させる

As the typhoon moved away, the wind along the coast gradually weakened, and the fishing boats began to go out to sea again.

The doctor prescribed him a new medicine; after taking it, the pain noticeably weakened, and he could finally sleep well.

Because it hadn't rained for a long time, the reservoir's water level kept dropping, and the capacity for hydroelectric power generation weakened accordingly.

Even though he tried hard to concentrate, the noise in the café still weakened his study efficiency quite a bit.