Check five fiery bursts (6)
I believe the answer is:
verify
'check' is the definition.
(I've seen this before)
'five fiery bursts' is the wordplay.
'five' becomes 'V' (roman numeral).
'bursts' indicates an anagram.
'fiery' anagrammed gives 'erify'.
'v'+'erify'='VERIFY'
(Other definitions for verify that I've seen before include "Ascertain truth or accuracy" , "Establish truth or accuracy of" , "Check (facts)" , "Confirm the truth of" , "Demonstrate" .)