Rushes to upset step-dames (9)
I believe the answer is:
stampedes
'rushes' is the definition.
The definition and answer can be both acts as well as being plural nouns.
Maybe you can see an association between them that I don't see?
'upset step-dames' is the wordplay.
'upset' indicates an anagram.
'step'+'dames'='stepdames'
'stepdames' is an anagram of 'STAMPEDES'.
'to' acts as a link.
Can you help me to learn more?
(Other definitions for stampedes that I've seen before include "Flights of frightened cattle" , "Wild headlong rushes of animals" , "Headlong rush of crowds" , "Takes flight like frightened cattle" .)