Cut red line, not squiggly (10)
I believe the answer is:
tenderloin
'cut' is the definition.
(tenderloin is a kind of cut)
'red line not squiggly' is the wordplay.
'squiggly' indicates anagramming the letters.
'red'+'line'+'not'='redlinenot'
'redlinenot' with letters rearranged gives 'TENDERLOIN'.
(Other definitions for tenderloin that I've seen before include "Fine cut of meat" , "soft meat" , "Joint" , "high crime rate here" , "best cut" .)