Found in the following dictionaries
SOWPODS (Collins Scrabble Words)
"Risp" Definition
noun
Scottish. A small serrated bar fixed upright on a house door, with a ring attached, which was forcibly rubbed up and down the bar to attract the attention of those inside. Now historical.
Source: Oxford Dictionary
Scottish. A grating or rasping sound.
Source: Oxford Dictionary
verb
To rub together, to rasp or grate.
Source: Wiktionary
To make a rasping or grating sound.
Source: Oxford Dictionary