Characterized by or involving covin; fraudulent, deceptive, or obtained through secret conspiracy.
From covin plus the -ous suffix, which transforms a noun into an adjective meaning 'full of' or 'characterized by' the noun's quality.
In medieval law, a 'covinous' contract could be voided entirely—one person couldn't secretly agree with a judge beforehand to unfairly rule against their opponent, or both would face severe punishment!
Complete word intelligence in one call. Free tier — 50 lookups/day.