Esoteric beggar can eat sandwiches (6)
I believe the answer is:
arcane
'esoteric' is the definition.
(similar in meaning)
'beggar can eat sandwiches' is the wordplay.
'sandwiches' indicates the answer is hidden within the clue (the answer is sandwiched in by the clue).
'ARCANE' is hidden within 'beggar can eat'.
(Other definitions for arcane that I've seen before include "deep" , "Secret, hidden" , "Mysterious, secret or obscure" , "Mysterious like a crane" , "Mysteriouss or secret" .)