These old Greeks lived frugally (8)
I believe the answer is:
spartans
'these old greeks lived frugally' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for spartans that I've seen before include "hardy fellows" , "These old Greeks lived frugally and harshly" , "Hardy and frugal citizens of old Greece" , "Hardy old Greeks" , "Harshly treated citizens once" .)