Fluctuating euros causing stir (5)
I believe the answer is:
'stir' is the definition.
(I've seen this in another clue)
'fluctuating euros' is the wordplay.
'fluctuating' indicates anagramming the letters.
'euros' with letters rearranged gives 'ROUSE'.
'causing' is the link.
(Other definitions for rouse that I've seen before include "Move" , "cause to wake or to become active" , "To start" , "Excite; awaken" , "Stir from inactivity" .)