Exceptional religious education with gospel expert (10)
I believe the answer is:
remarkable
'exceptional' is the definition.
(thesaurus)
'religious education with gospel expert' is the wordplay.
'religious education' becomes 'RE' (abbreviation).
'with' says to put letters next to each other.
'gospel' becomes 'Mark' (Gospel of Mark).
'expert' becomes 'able' (I've seen this before).
're'+'mark'+'able'='REMARKABLE'
(Other definitions for remarkable that I've seen before include "Striking" , "Noteworthy" , "surprising?" , "Extraordinary" , "A wrongly-graded exam paper" .)