Deadly light artillery piece cut down lancer at front (6)

I believe the answer is:

mortal

I'm a little stuck... Click here to teach me more about this clue!

'deadly' is the definition.
(I know that deadly can be written as mortal)

I don't understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for mortal that I've seen before include "Sound a wound is deadly" , "Liable to cause death" , "liable to die" , "Destined to die" , "Subject to death, like all mankind" .)

I've seen this clue in The Independent.

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.