Powerless as nebula transforms (6)

I believe the answer is:

unable

(Other definitions for unable that I've seen before include "Not having sufficient power" , "Lacking the required capacity" , "Lacking the necessary skills" , "Not fit or competent" , "Not in a position (to)" .)

I've seen this clue in The Sun.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.