1To lean against or rest on something (physically), to recline on a support.
電車で疲れて壁にもたれて眠ってしまった。
I was tired on the train and ended up falling asleep leaning against the wall.
カフェで窓にもたれて景色を眺めた。
I leaned by the window in the café and looked at the view.
彼はテーブルにもたれて熱心に話を聞いていた。
He was leaning on the table and listening intently.
2To sit heavy in the stomach; to be hard to digest, causing discomfort.
昨夜脂っこいものを食べ過ぎて、今朝は胃がもたれている。
I ate too much greasy food last night and my stomach feels heavy this morning.
この料理は胃にもたれやすいので、少なめに食べた方がいい。
This dish is easy on the stomach; it's better to eat it in small amounts.
牛乳を飲むと胸焼けともたれる感じがする人もいる。
Some people feel heartburn and a heavy sensation in the stomach after drinking milk.