Dubious Implications

Dubious is an insidious, double-dealing word. Related to double? Probably Latin.

It means doubtful, equivocal, or suspicious. It comes from Dubium, Latin for doubt.

Equivocal means ambiguous, doubtful, or suspicious.

Insidious means subtly cunning or deceitful.

So dubious is less insidious than insidious. Insidious is more egregious.

Egregious is conspicuously bad, flagrant. From Latin also.

Whether somone is dubious or insidious would depend on whether they were intentionally ambiguous or just innocently unclear.