Mild oath referring to restless sort (8)
I believe the answer is:
'restless sort' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for gadabout that I've seen before include "Restless seeker after amusement", "restless sort", "restless type", "Person who goes around aimlessly", "Person who wanders aimlessly in search of pleasure".)