Charming river flowing west around German isle (5)
I believe the answer is:
magic
'charming' is the definition.
(thesaurus)
'river flowing west around german isle' is the wordplay.
'river' becomes 'cam' (I've seen this before).
'flowing west' says the letters should be written in reverse (written from right to left or 'east to west').
'around' means one lot of letters goes inside another.
'german' becomes 'g' (abbreviation).
'isle' becomes 'i'.
'cam' in reverse letter order is 'mac'.
'g'+'i'='gi'
'mac' going around 'gi' is 'MAGIC'.
(Other definitions for magic that I've seen before include "Fungus causing trips?" , "Prestidigitation" , "Witchcraft" , "Superb" , "Enchantment" .)