To become thin; to lose weight; to slim down (usually referring to the body).
健康のために少し痩せたいと思っている。
I want to lose a little weight for my health.
彼は毎日ジョギングしてだいぶ痩せた。
He jogged every day and lost a lot of weight.
食欲がないせいで痩せてしまった。
I lost weight because I had no appetite.
モデルのように急に痩せるのは健康に良くない。
Suddenly slimming down like a model isn't good for your health.
To become impoverished or infertile (of soil); to lose nutrients and become poor for cultivation; also used metaphorically for decline of resources or strength.
長年の単作で畑が痩せてしまった。
After years of monoculture the fields became depleted.
森林伐採で土地が痩せるのを防がなければならない。
We must prevent the land from becoming impoverished due to deforestation.