to talk nonsense, to talk rubbish
Não leve a sério o que ele disse, ele estava bêbado e falando abobrinha.
Don't take what he said seriously, he was drunk and talking nonsense.
Here abobrinha ("little squash/zucchini") was the nickname of an old Brazilian banknote: the 1,000-cruzeiro note that circulated from the 1940s to the 1960s, called that because its colour recalled the squash fruit. As galloping inflation ate away its value, the once-prized note became practically worthless.
Sources: HR Idiomas, Portal Litoral Sul.
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