Some niggas watch you
See you when you think on the low
(On the low) is a phrase that essentially means doing something that no one will notice.
For example: “I’m smiling in her face, but I’m laughing at her on the low.” Meaning you’re giving her the impression of content but secretly making fun of her.
Nas' is stating that as you may think you’re on the low(as if you’re secretly moving and no one is watching you) some people actually are.
To help improve the meaning of these lyrics, visit “Watch Dem Niggas” by Nas (Ft. Foxy Brown) Lyrics and leave a comment on the lyrics box