Emulate 3-Down, with "it" (3)

I believe the answer is:

dog

(Other definitions for dog that I've seen before include "Hound" , "Follow - canine" , "St Bernard, for example" , "Lassie" , "'You cannot teach an old ... new tricks'" .)

I've seen this clue in the Newsday.

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.