A strange tailless cat making a row (6)
I believe the answer is:
'a row' is the definition.
(both can mean a controversy or dispute)
'a strange tailless cat' is the wordplay.
'a strange' becomes 'rum' (I've seen this before).
'tailless' means to remove the last letter (the tail of the word is removed).
'cat' becomes 'puss' (puss is a kind of cat).
'puss' with its final letter taken away is 'pus'.
'making' is the link.
(Other definitions for rumpus that I've seen before include "Noisy brawl" , "Tumult" , "Row" , "Noisy, disruptive commotion" , "Hullabaloo" .)