1. done in secret or without permission; stealthy and secretive

Examples

• She took a surreptitious glance at her phone during the meeting.
• The spy made a surreptitious exit through the back door.
• He gave his friend a surreptitious wink across the room.
• The student made surreptitious notes on her palm before the test.
• They had a surreptitious conversation in the hallway.
• The cat made a surreptitious approach toward the bird feeder.