Some hiker hurried over European river (4)
I believe the answer is:
ruhr
'european river' is the definition.
'ruhr' can be an answer for 'river' (I've seen this before). I am not sure about the 'european' bit.
'some hiker hurried over' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'over' says the letters should be written in reverse.
'rhur' is hidden within 'hiker hurried'.
'rhur' in reverse letter order is 'RUHR'.
Can you help me to learn more?
(Other definitions for ruhr that I've seen before include "Herman industrial area" , "River and industrial region of northwest Germany" , "Dortmund area?" , "German industrial area" , "Major industrial region of north-west Germany" .)