to gain weight; to put on weight; to fatten (oneself/someone/something up)
Engordar demais não é bom para a saúde.
Gaining too much weight isn't good for your health.
I don't want to gain weight.
Algumas mulheres tomam medicamentos para engordar rapidamente.
Some women take medication to gain weight quickly.
Se você comer tanto assim, vai engordar.
If you eat that much, you'll gain weight.
Eu ficarei, se conseguir não engordar até mês que vem.
I'll stay, if I manage not to gain weight until next month.
— TÁR (2022)