Likely to get riled about new, expensive clothes? (6)
I believe the answer is:
finery
'clothes?' is the definition.
(finery is a kind of clothes)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for finery that I've seen before include "Elaborate clothes and accessories" , "Showy clothing" , "Ostentatious clothes" , "Glad rags, best duds" , "Ostentatious decoration" .)