Scorn prophet welcoming knight on board (5)
I believe the answer is:
sneer
'scorn' is the definition.
(sneer is a kind of scorn)
'prophet welcoming knight on board' is the wordplay.
'prophet' becomes 'seer' (I've seen this before).
'welcoming' indicates putting letters inside (in sense of 'inviting in').
'knight on board' becomes 'N' (chess abbreviation for knight).
'seer' placed around 'n' is 'SNEER'.
(Other definitions for sneer that I've seen before include "Speak contemptuously" , "Dig" , "Scoff, scorn" , "Smile contemptuously" , "Show contempt by contorting the face" .)