surreptitious /sur-əp-tishˈəs/

1. Done by stealth or fraud
2. Stealthy

surreptiˈtiously adverb

• tricklings
• trickly
• trick or treat
• tricks
• tricksier
• tricksiest
• tricksily
• tricksiness
• tricksinesses
• tricksome
• trickster
• trickstering
• tricksterings
• tricksters
• tricksy
• trick-track
• trick-tracks
• tricky
• triclinia
• triclinic
• triclinium
• triclosan
• tricolor
• tricolors
• tricolour