Noun, する verb, and の adjective
そくし
彼は潮津波に乗ってサーフィンをしようとしたが、残念ながら即死した。
He tried to ride tidal bore and surf it, but unfortunately he died instantly.
An instant death is an instant death.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.