Toughened up, accepting Jack's hurt (7)
I believe the answer is:
injured
'hurt' is the definition.
(similar in meaning)
'toughened up accepting jack's' is the wordplay.
'toughened up' becomes 'inured' (I've seen this in another clue).
'accepting' means one lot of letters goes inside another (inserted letters are accepted).
'jack' becomes 'J' (playing card abbreviation).
'inured' enclosing 'j' is 'INJURED'.
(Other definitions for injured that I've seen before include "Wounded" , "Harmed" , "caused hurt" , "wronged" .)