Stealthy
If by secretly you meant cautiously then walking stealthily or tip toeing .
The word is "eavesdropping."
I entered the room stealthily, hoping to remain unnoticed.
He stealthily snuck into the clock tower known as Big Ben
The cat moved stealthily through the dark hallway, its steps silent and its movements careful to not disturb anything.
She stealthily approaches the cake cupboard."I will move very stealthily," said the would-have-been diamond thief, seconds before he tripped a laser-triggered alarm.The Royal Commandos stealthily kidnap their target for interrogation.
Edge only has one syllable. This means the whole word is the syllable.
Stealthy , stealthily ,ninja
It means City on the Edge.
Brim.
Frontier
Here's an example:The thieves sneaked stealthily through the household, savoring the prospect of some 'well-deserved' money.Hope it isn't too soppy for you...