Get a hundred to join singers on the radio (7)
I believe the answer is:
acquire
'get' is the definition.
(I know that get can be written as acquire)
'a hundred to join singers on the radio' is the wordplay.
'hundred' becomes 'c' (Roman numeral).
'to join' says to put letters next to each other.
'singers' becomes 'choir' (group of singers).
'on the radio' indicates a 'sounds like' (homophone) clue.
'choir' sounds like 'quire'.
'a'+'c'+'quire'='ACQUIRE'
(Other definitions for acquire that I've seen before include "Come to possess" , "Procure" , "Gain, obtain" , "Bag" , "Get" .)