Curglaff
From Openwaterpedia

Ram Barkai of the International Ice Swimming Association swimming in Antarctica about to experience curglaff
noun - Curglaff refers to the shock felt in swimming when one first enters into cold water.
Usage[edit]
Ice swimmers experience curglaff at water temperatures near 0°C.
Origin[edit]
From John Jamieson's Etymological Scottish Dictionary, 18th century.