Repeat insult coming from touchlines (4)

I believe the answer is:

echo

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

'repeat' is the definition.
('echo' can be a synonym of 'repeat')

I can't explain the rest of the clue.

(Other definitions for echo that I've seen before include "Repeated sound" , "She loved Narcissus - it's recalled" , "What evokes memories" , "Repetition of sound" , "Reminder" .)

I've seen this clue in the Irish Times.

Want a hint initially instead of a full solution? Install my app