Step out with mad European in a beastly rush (8)
I believe the answer is:
stampede
'beastly rush' is the definition.
'stampede' can be an answer for 'rush' (I've seen this before). I am not certain of the 'beastly' bit.
'step out with mad european' is the wordplay.
'out with' indicates anagramming the letters (out can mean wrong or inaccurate).
'european' becomes 'e' (abbreviation e.g. EU).
'step' anagrammed with 'mad' makes 'stamped'.
'stamped'+'e'='STAMPEDE'
'in a' acts as a link.
Can you help me to learn more?
(Other definitions for stampede that I've seen before include "Flight of cattle in panic" , "Panicky run" , "Crazy pets made a sudden rush" , "Panicked rush (of cattle)" , "Beastly charge" .)