Tome half in Latin thus enduring (5)
I believe the answer is:
stoic
'enduring' is the definition.
(thesaurus)
'tome half in latin thus' is the wordplay.
'half' indicates taking half.
'in' indicates putting letters inside.
'latin thus' becomes 'sic' (I can't explain this - if you can you should believe this answer much more).
'tome' halved is 'to'.
'to' put into 'sic' is 'STOIC'.
Can you help me to learn more?
(Other definitions for stoic that I've seen before include "Resigned" , "Able to endure pain" , "One showing endurance during adversity" , "Person indifferent to pleasure or pain" , "Athenian philosopher" .)