Wandering south with many (8)
I believe the answer is:
thousand
'many' is the definition.
(thesaurus)
'wandering south with' is the wordplay.
'wandering' indicates anagramming the letters.
'with' becomes 'and'.
'south' anagrammed gives 'thous'.
'thous'+'and'='THOUSAND'
(Other definitions for thousand that I've seen before include "Roman numeral M" , "Ten cubed" , "quite a lot" , "M or K" , "-- Island dressing" .)