Study and crack examination without tension primarily (6)
I believe the answer is:
digest
'study' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for digest that I've seen before include "Take in - collected rules of laws" , "Periodical that summarises the news" , "Break down in the stomach" , "book" , "Summary or shortened version" .)