The story
From Mandarin 給力 /给力 (gěilì, “to give power; to be powerful, awesome”) + -able. Perhaps a back-formation from ungelivable (“uninteresting, unexciting”), which was modelled on unbelievable.
Etymology from Wiktionary, CC BY-SA 4.0.
gelivable
Today it means: Awesome, incredible, amazing, extraordinary. Full definition →