Back head abandoning exam, it's most rigorous (8)
I believe the answer is:
sternest
'most rigorous' is the definition.
Both the definition and answer are superlative adjectives. Maybe there's a link between them I don't understand?
'back head abandoning exam' is the wordplay.
'back' becomes 'stern' (I've seen this before).
'head abandoning' means to remove the first letter (I've seen 'head abandons' mean this).
'exam' becomes 'test' ('test' can be a synonym of 'exam').
'test' with its first letter taken away is 'est'.
'stern'+'est'='STERNEST'
'it's' is the link.
Can you help me to learn more?
(Other definitions for sternest that I've seen before include "Most unfriendly" , "Most severe and unrelenting" , "Most strict and demanding" , "Strictest or grimmest" , "Most serious and unrelenting" .)