Scintillating secret agent captures boat (6)
I believe the answer is:
sparky
'scintillating secret' is the definition.
The definition suggests a singular noun which matches the answer.
'agent captures boat' is the wordplay.
'agent' becomes 'spy' (spy is a kind of agent).
'captures' indicates putting letters inside.
'boat' becomes 'ark' (ark is a kind of boat).
'spy' going around 'ark' is 'SPARKY'.
Can you help me to learn more?
(Other definitions for sparky that I've seen before include "Lively, high-spirited" , "Clever and enjoyable to be with" , "Spirited" , "jaunty" .)