Mechanical repetition featured in rhetorician's retreat (4)
I believe the answer is:
rote
'mechanical repetition' is the definition.
(I've seen this before)
'featured in rhetorician's retreat' is the wordplay.
'featured in' says the answer is hidden in the clue.
'retreat' is a reversal indicator.
'etor' is hidden in the letters of 'rhetoricians'.
'etor' back-to-front is 'ROTE'.
(Other definitions for rote that I've seen before include "Repetition from memory" , "performance based solely on routine" , "By . . . . - by memory without thinking" , "By . . . . means by memory - that tore it" , "Learn by ____ (repetition)" .)