1. Playful in an appealingly bold way
   - devilish, roguish 
2. Lacking principles or scruples
   "the rascally rabble"
   - roguish, scoundrelly, blackguardly

See also: dishonest, dishonorable [US], dishonourable [Brit, Cdn], playful, rascal

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• bioluminescence
• bioluminescent