Blues or pop singer catches finale from The Jam (10)
I believe the answer is:
depression
'blues' is the definition.
(I've seen this before)
'pop singer catches finale from the jam' is the wordplay.
'pop singer' becomes 'dion' (Celine Dion).
'catches' means one lot of letters goes inside another.
'finale from' suggests the final letters.
'jam' becomes 'press' (synonyms).
The final letter of 'the' is 'e'.
'e'+'press'='epress'
'dion' enclosing 'epress' is 'DEPRESSION'.
'or' acts as a link.
(Other definitions for depression that I've seen before include "gloom" , "Pit" , "Blues" , "Nineteen twenty nine financial slump" , "valley" .)