0 thought not to be completely true, honest, or legal -- dubbio, equivoco
a man with a dubious reputation un uomo di dubbia reputazione
dubious evidence prove dubbie
1 not certain that something is good or true -- dubbioso, incerto
He’s dubious about the benefits of acupuncture. Ha dei dubbi sui benefici dell’agopuntura.
2 doubtful -- dubbioso, incerto
3 probably not honest -- equivoco
dubious behaviour/behavior.