Green’s Dictionary of Slang

stellar adj.

excellent, wonderful, ‘out of this world’.

[US]Eble Campus Sl. Nov.
Online Sl. Dict. [Internet] stellar adj 1. very good, excellent; COOL, AWESOME. (‘That was some stellar movie we saw last night.’).
OnLine Dict. of Playground Sl. [Internet] stellar adj. Similar to ‘amazing’, ‘awesome’, ‘mega’ etc. e.g. ‘That haircut is great – really stellar!’.