Ruthless examination for PhD? (5,6)
I believe the answer is:
third degree
This clue could be a double definition.
'ruthless examination' is the first definition.
'third degree' can be an answer for 'examination' (third degree is a kind of examination). I am unsure of the 'ruthless' bit.
'phd?' is the second definition.
(I've seen this in another clue)
'for' is the link.
Can you help me to learn more?
(Other definitions for third degree that I've seen before include "Extremely severe examination" , "doctorate, possibly?" , "Intense grilling" , "Post-doctorate" , "Relentless questioning" .)