gold-digger marriage, to marry for money
Ela casou com ele, ela tem 25 anos e ele 60. Ela é mestra em dar o golpe do baú!
She married him, she is 25 and he is 60. She is a master gold digger!
The expression golpe do baú (literally "the chest trick") goes back to a time when families kept their valuables — money, jewels and a daughter's wedding trousseau — in a sturdy chest, the baú. To marry well was, in effect, to lay hands on someone else's chest, and the phrase came to brand a marriage entered into purely for the partner's fortune.
Source: Jornal de Beltrão.
Falando's Idiom Trainer teaches you to recognize idiom meanings and create sentences using them, so you can speak like a Brazilian.