Highly decorated knight coming in to make a speech (6)
I believe the answer is:
ornate
'highly decorated' is the definition.
(I've seen this before)
'knight coming in to make a speech' is the wordplay.
'knight' becomes 'n' (chess).
'coming in to' means one lot of letters goes inside another.
'make a speech' becomes 'orate' (I've seen this before).
'n' put inside 'orate' is 'ORNATE'.
(Other definitions for ornate that I've seen before include "Over-decorated" , "Are not (anag.)" , "Highly embellished" , "Detailed" , "Lavishly decorated" .)