Working hollow platitude into speech (9)
I believe the answer is:
operation
'working' is the definition.
(how something operates)
'hollow platitude into speech' is the wordplay.
'hollow' says to hollow out the word (remove centre letters) (the word is hollowed out).
'into' is an insertion indicator.
'speech' becomes 'oration' (oration is a kind of speech).
'platitude' with its middle taken out is 'pe'.
'pe' going inside 'oration' is 'OPERATION'.
(Other definitions for operation that I've seen before include "Surgical or military piece of work" , "Action; process" , "Handling" , "To one pair (anag.)" , "Procedure; enterprise" .)