Cross about Europe of course (6)
I believe the answer is:
surely
'of course' is the definition.
(thesaurus)
'cross about europe' is the wordplay.
I cannot quite understand how this works, but
'about' could be 're' ('re' means regarding or about) and 're' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for surely that I've seen before include "Indubitably" , "Without doubt, certainly" , "that's for certain" , "With certainty" , "Undoubtedly" .)