Show-off that's more 'sophisticated' rejecting last bit of sandwich (5)
I believe the answer is:
poser
'show-off' is the definition.
(poser is a kind of show-off)
'more sophisticated rejecting last bit of sandwich' is the wordplay.
'POSER' is hidden backwards in amongst the letters.
However, I'm not sure how this is indicated.
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for poser that I've seen before include "insincere?" , "Brain-teaser" , "Question - a sitter" , "Exhibitionist" , "What's difficult" .)