Lively composition Dawn scored ineptly (5,5)
I believe the answer is:
sword dance
'lively composition' is the definition.
(dance done with swords)
'dawn scored ineptly' is the wordplay.
'ineptly' indicates an anagram (an inept spelling).
'dawn'+'scored'='dawnscored'
'dawnscored' is an anagram of 'SWORD-DANCE'.
(Other definitions for sword dance that I've seen before include "Jig, caper over blades" , "Performance involving sharp weapons" , "steps with much arm-waving" , "Pre-war ritual" , "Potentially dangerous steps" .)