Ability to withstand hardship shown by European scratching head in daze (9)
I believe the answer is:
tolerance
'ability to withstand hardship' is the definition.
(ability to tolerate difficulties)
'european scratching head in daze' is the wordplay.
'european' becomes 'pole' (someone from Poland).
'scratching head' means to remove the first letter (the word's head is removed).
'in' is an insertion indicator.
'daze' becomes 'trance' (I've seen this before).
'pole' with its first letter removed is 'ole'.
'ole' put inside 'trance' is 'TOLERANCE'.
'shown by' is the link.
(Other definitions for tolerance that I've seen before include "Acceptance - permitted variation in measurement" , "broad-mindedness" , "Ability to endure something" , "Patience, forbearance" , "See 10" .)