Indulging only covertly

• Having an import not apparent to the senses nor obvious to the intelligence
• Squirrel, at times
• Not openly made known
• Designed to elude detection
• Kept private or not revealed
• Not expressed
• The next to highest level of official classification for documents
• Beyond ordinary understanding

Wiktionary Word definitions in Wiktionary
n. (alternative spelling of secretor English)