surf (n.)
1680s, probably from earlier suffe (1590s), of uncertain origin. Originally used in reference to the coast of India, hence perhaps of Indic origin. Or perhaps a phonetic respelling of sough, which meant "a rushing sound."
surf (v.)
"ride the crest of a wave," 1917, from surf (n.). Related: Surfed; surfing. In the Internet sense, first recorded 1993.