Green’s Dictionary of Slang

shade n.4

[ety unknown; ? play on SE place in a poor light]

(US) an insult.

[US]C. Eble UNC-CH Campus Sl. Spring 2014 13: SHADE — insult, an offensive comment: ‘No shade. But you may want to wear something else’.
[US]J. Hannaham Didn’t Nobody Give a Shit 125: I’ma get me some blood all over this here $250 Amanda shoe if this man don’t cut it out with all the shade.

In phrases

throw shade (v.)

(US) to criticize negatively, to pass judgement on.

[US]C. Eble UNC-CH Campus Sl. Spring 2014 15: THROW SHADE — pass judgment on someone, insult.
email to http://languagelog.ldc.upenn.edu 8 Sept. 🌐 throw shade to talk trash about a friend or aquaintance, to publicly denounce or disrespect. When throwing shade it's immediately obvious to on-lookers that the thrower, and not the throwee, is the bitchy, uncool one.
Twitter 10 Oct. 🌐 Excellent shade being thrown by the art department here. (By using literal shade to make her look wide af).
[US]S.A. Crosby Razorblade Tears 68: He’d never thrown any shade at him for being a chef.