Margin outside themselves (3)
I believe the answer is:
hem
'margin' is the definition.
(I've seen this in another clue)
'outside themselves' is the wordplay.
'HEM' is hidden in amongst the letters.
But, I am not sure how this is indicated.
Can you help me to learn more?
(Other definitions for hem that I've seen before include "Part of skirt" , "Double-backed cloth border" , "Border; fringe" , "Finished edge of a piece of cloth" , "may attract attention" .)