Green’s Dictionary of Slang

natty adj.

[all SE by late 19C]
[late 18C+]

1. of individuals, well-dressed, smart.

2. of objects, typically clothing, neat, spruce.

3. adept with the hands; skilful in any manner.

In compounds

natty lad (n.) (also natty, natty kid)

[late 18C–mid-19C] a young thief or pickpocket.