Whole time alto performed (5)
I believe the answer is:
total
'whole' is the definition.
(total is a kind of whole)
'time alto performed' is the wordplay.
'time' becomes 't'.
'performed' indicates anagramming the letters.
'alto' anagrammed gives 'otal'.
't'+'otal'='TOTAL'
(Other definitions for total that I've seen before include "Entire sum" , "French oil and gas company" , "Complete, entire amount" , "Comprising the whole" , "The whole number" .)