The phrase "did sly" can mean to act in a sneaky or underhanded manner. There are several synonyms for this phrase that can be used interchangeably to convey the same idea. Some of these synonyms include "behaved deceitfully," "acted guilefully," "revealed cunning," or "showed craftiness." Other related words that can be used to describe someone who is behaving slyly include "sneaky," "shiftily," or "deviously." These words can be used to describe anything from a crafty business strategy to a mischievous prank. Regardless of the context, when someone is acting slyly, it's important to be aware of their intentions and motives.