Uncover origins of really expensive meat (6)
I believe the answer is:
reveal
'uncover' is the definition.
(synonyms)
'origins of really expensive meat' is the wordplay.
'origins of' says to take the initial letters.
'meat' becomes 'veal' (veal is a kind of meat).
The first letters of 'really expensive' is 're'.
're'+'veal'='REVEAL'
(Other definitions for reveal that I've seen before include "Final disclosure" , "Uncover or expose" , "Expose, remove covering" , "Disclose or uncover" , "Open up" .)