Endless task overwhelming current group of singers (5)
I believe the answer is:
choir
'group of singers' is the definition.
(I've seen this before)
'endless task overwhelming current' is the wordplay.
'endless' means to remove the last letter.
'task' becomes 'chore' (synonyms).
'overwhelming' indicates putting letters inside.
'current' becomes 'I' (symbol for electric current).
'chore' with its last letter taken away is 'chor'.
'chor' enclosing 'i' is 'CHOIR'.
(Other definitions for choir that I've seen before include "Singing group" , "Body of singers" , "Vocal group" , "Chorus in church" , "Singers in harmony" .)