spelunkern.

1942 A. F. Harlow Weep no More, my Lady xxiii. 407 A young man named Floyd Collins, a native of the hills a few miles north of the Mammoth, had long been a confirmed ‘spelunker’, or cave bug.

1946 Life 4 Nov. 143 Cave exploring,..which bears the scientific name of speleology, has a group of amateur followers who like to call themselves ‘spelunkers’.

1965 P. Ordway Night of Reckoning (1967) 131 Not being a spelunker at heart, let's hope..there aren't too many bats.

1971 G. G. Luce Body Time ii. 54 A courageous spelunker and geologist, Michel Siffre, who spent two months on a subterranean glacier in the French Alps in 1962.

1980 ‘E. McBain’ Ghosts viii. 155 The cave seemed not in the least bit inviting. He had always considered spelunkers the choicest sorts of maniacs.

1965 R. McDowell Hound's Tooth vii. 105 They had no legitimate complaint if he chose to take Jenny spelunking in Hunter's Cave.

1946 Life 4 Nov. 143 (heading) Life goes spelunking.

1959 Weekend 12 Sept. 77/2 To take a second look at Cadomin caves Weekend organized another spelunking expedition.

1974 Islander (Victoria, Brit. Columbia) 8 Dec. 15/3 Spelunking..is a sport which has become popular within our time.

1979 United States 1980–1 (Penguin Travel Guides) 563 You can see these on..walks through the cave,..and on spelunking tours where you do your own locomoting on all fours.