One after another mentioned trainee (6)
I believe the answer is:
intern
'trainee' is the definition.
(intern can mean a trainee worker)
'one after another mentioned' is the wordplay.
'one after another' becomes 'inturn' (in turn means one by one).
'mentioned' shows a homophone (sound like).
'inturn' is a homophone of 'INTERN'.
(Other definitions for intern that I've seen before include "Confine - physician in US hospital" , "Hold in custody" , "Imprison (enemy aliens)" , "22 [IMPRISON]" , "Confine - assistant medic in America" .)