Maggie, to Bart

I believe the answer is:

sis

(Other definitions for sis that I've seen before include "Relative's" , "relative" , "Girl" , "Secret Intelligence Service (abbreviation)" , "Sibling (informal)" .)

I've seen this clue in The Mirror.

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.