Spank husband mixing with riff-raff (6)
I believe the answer is:
thrash
'spank' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for thrash that I've seen before include "Wallop" , "Hit hard" , "Administer sound beating to" , "Beat up, batter" , "Decisively beat" .)