Polite word of request (6)
I believe the answer is:
please
'polite word of request' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for please that I've seen before include "Like" , "Gratify, make contented" , "Satisfy while asleep" , "If you'd be so kind?" , "Gratify or ask nicely" .)