insidious

• Décrit quelque chose qui est nuisible, dangereux ou perfide de manière discrète, se propageant souvent progressivement et passant inaperçu.

Describes something that is subtly harmful, dangerous, or deceitful, often spreading gradually without being noticed.

1. Subtly harmfulC1formal

   Proceeding in a gradual, subtle way but with harmful effects.

   insidieux (nuisance sournoise)

   • The insidious disease spread without any early symptoms.
   • Prejudice can have an insidious effect on society.
   • The insidious influence of propaganda eroded public trust.

   Synonymescorrosivedeceptiveperniciousstealthysubtletreacherousunderhanded

   Antonymesblatantdirectflagrantobviousovert

2. Treacherous or deceitfulC1formal

   Intended to entrap or deceive in a cunning way.

   insidieux (sens trompeur)

   • The insidious plot was designed to overthrow the government.
   • He used insidious tactics to manipulate his colleagues.
   • The insidious nature of the scheme made it hard to detect.

   Synonymescraftycunningdeceitfulguilefulslysubtletreacherousunderhandedwily

   Antonymescandidforthrightguilelesshonestopenstraightforward