Working in operas with bass singers - ultimately, they're often cast (10)
I believe the answer is:
aspersions
'often cast' is the definition.
Although both the answer and 'cast' are nouns, they are not in the same form of the noun.
'working in operas with bass singers ultimately' is the wordplay.
'working' is an anagram indicator.
'with' is a charade indicator (letters next to each other).
'ultimately' suggests the final letters.
The last letters of 'bass singers' are 'ss'.
'in'+'operas'='inoperas'
'inoperas' after 'ss' is 'ssinoperas'.
'ssinoperas' is an anagram of 'ASPERSIONS'.
'they're' is the link.
Can you help me to learn more?
(Other definitions for aspersions that I've seen before include "Slanders" , "slanderous accusations" , "derogatory remarks" .)