Tramp stumbles around atomic base (7)
I believe the answer is:
traipse
'tramp' is the definition.
(thesaurus)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for traipse that I've seen before include "long tiring walk" , "Trudge around" , "Trudge or tramp in parties" , "Tedious walk" , "Plod - trek" .)