Dallas family for example embodies success (5)
I believe the answer is:
ewing
'dallas family' is the definition.
(I've seen this in another clue)
'example embodies success' is the wordplay.
'example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'embodies' indicates putting letters inside.
'success' becomes 'win' (I've seen this in another clue).
'eg' enclosing 'win' is 'EWING'.
'for' acts as a link.
(Other definitions for ewing that I've seen before include "Fictional oil baron" , "Oil family" .)