secret or dishonest activity or behavior

धोखाधड़ी या गलत काम करना

English Usage: Their plans were filled with skulduggery that eventually led to their downfall.

Hindi Usage: उनकी योजनाएं धोखाधड़ी से भरी हुई थीं जो अंततः उनकी गिरावट की ओर ले गई।