Being concealed for evil purposes (7)

I believe the answer is:

lurking

(Other definitions for lurking that I've seen before include "Lying in wait, to ambush say" , "Waiting in ambush" , "Lying hidden in ambush" , "Skulking" , "Lying in wait, ready to ambush perhaps" .)

I've seen this clue in the Sydney Morning Herald.

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.