Go around Australia with a philosopher (7)
I believe the answer is:
spinoza
'philosopher' is the definition.
(Baruch Spinoza)
'go around australia with a' is the wordplay.
'go around' becomes 'spin' (spinning is a kind of going around).
'australia' becomes 'oz' (informal name for Australia).
'with' means one lot of letters go next to another.
'spin'+'oz'+'a'='SPINOZA'
(Other definitions for spinoza that I've seen before include "C17 Dutch philosopher" , "philosophical sort" , "2 [PHILOSOPHER]" , "Dutch 17th-century philosopher" .)