FWP:
For background see S. R. Faruqi's choices. This is NOT one of his choices; I thought it was interesting and have added it myself. For more on Ghalib's unpublished verses, see the discussion in {4,8x}.
If it wasn't necessarily Doomsday (for Doomsday examples see {10,11}), it was obviously something disruptive that Asad was waiting for. The term fitnah has strongly negative associations (see the definition above); it was one of the terms Sir Sayyid Ahmad Khan used for the rebellion of 1857.
Yet it also appears, in the second line, that the fitnah Asad was waiting for was some form of Divine manifestation. The word tajallii is a strong hint: other verses like {60,11} and {95,3} also associate it with an epiphany of some kind; while in {231,1}, as in the present verse, it keeps company with :zuhuur , another suggestive word that hints at a Divine presence.
Why then does the Divine manifestation appear as fitnah ? Perhaps because it seemed to appear as a candle, while Asad was a Moth destined always, 'in every color/style', to burn. So did the glory of the appearance of God itself appear as a kind of fitnah -- a disruptive experience, a 'temptation', an invitation to self-destruction? Or was the fitnah , in the form of self-immolation, all his own? Was he taking a forbidden, even rebellious, liberty?
For more on noun compounds like fitnah-inti;zaar
, see {129,6x}.
Zamin:
The meaning is that Asad, who was a Moth of the radiance of the candle of appearance-- that is, of the splendor of the effects/traces of Divinity-- in every color/way (that is, every sign of Divinity) remained possessed and mad with the tokens of Divinity.
== Zamin, p. 62