General Brazilian
proposta desonesta / proposta ardilosa
Most commonly used in formal and informal contexts
Rio de Janeiro
proposta furada / proposta cilada
More colloquial, slang usage in casual speech
São Paulo
proposta desonesta / proposta suspeita
Formal business context; more cautious language
Portugal
proposta desonesta / proposta traiçoeira
European Portuguese variant; emphasizes betrayal aspect