Furrow brow after losing case embraced by politician (6)
I believe the answer is:
groove
'furrow' is the definition.
(I know that furrow can be written as groove)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for groove that I've seen before include "Long shallow depression or routine" , "Long thin furrow" , "Long narrow cut in hard material" , "Spiral track followed by a gramophone needle" , "Kind of furrow or rut" .)