Obstruction exists about Romanian money (5)
I believe the answer is:
ileus
'obstruction' is the definition.
(I know that ileus is a type of obstruction)
'exists about romanian money' is the wordplay.
'exists' becomes 'is' (if something 'is', it exists).
'about' means one lot of letters goes inside another.
'romanian money' becomes 'leu' (I've seen this in another clue).
'is' placed around 'leu' is 'ILEUS'.
(Other definitions for ileus that I've seen before include "A bad gut feeling" , "A nasty gut feeling" , "Medical condition" .)