Lower classes take frivolous pleasure (7)
I believe the answer is:
delight
'pleasure' is the definition.
('delight' can be a synonym of 'pleasure')
'lower classes take frivolous' is the wordplay.
'lower classes' becomes 'de' (I've seen this in other clues).
'take' means one lot of letters go next to another.
'frivolous' becomes 'light' (I've seen this before).
'de'+'light'='DELIGHT'
(Other definitions for delight that I've seen before include "Greatly please" , "Felicity" , "Gladden" , "charm" , "See 5" .)