<p><strong>Adjective:</strong></p><ul><li>Intended to entrap or beguile:<ul><li>Example: An insidious plan.</li></ul></li><li>Stealthily treacherous or deceitful:<ul><li>Example: An insidious enemy.</li></ul></li><li>Operating or proceeding in an inconspicuous or seemingly harmless way but actually with grave effect:<ul><li>Example: An insidious disease.</li></ul></li></ul><p><strong>Synonyms:</strong></p><ul><li>Crafty</li><li>Subtle</li><li>Wily</li><li>Cunning</li><li>Artful</li></ul><p><strong>End of Response</strong></p>