Thug taking fur up - loud man (7)
I believe the answer is:
ruffian
'thug' is the definition.
(I've seen this before)
'fur up loud man' is the wordplay.
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'loud' becomes 'f' (short for forte - 'loud' in music).
'man' becomes 'ian' (man's name).
'fur' back-to-front is 'ruf'.
'ruf'+'f'+'ian'='RUFFIAN'
'taking' acts as a link.
(Other definitions for ruffian that I've seen before include "Rowdy" , "Hooligan" , "Bully" , "Violent, lawless person" , "Aggressive, rude troublemaker" .)