Exaggerated the acceleration Concorde initially recorded during test (10)
I believe the answer is:
theatrical
'exaggerated' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for theatrical that I've seen before include "Excessively dramatic" , "overdramatic" , "Stagy" , "Relating to acting/actors" , "Artificial and exaggerated" .)