SLY, adjective 1. Artfully dextrous in performing things secretly, and escaping observation or detection; usually implying some degree of meanness; artfully cunning; applied to persons; as a sly man or boy. 2. Done with artful and dextrous secrecy; as a sly trick. 3. Marked with artful secrecy; as sly circumspection. 4. Secret; concealed. Envy works in a sly imperceptible manner. SLY'-BOOTS, noun A sly cunning or waggish person.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI