Sentence:  I took to fishing, on mountain brooks and lakes, and finally I was inveigled into becoming a <WSD>spelunker</WSD>. A <WSD>spelunker</WSD> is a human worm who crawls into caves ("splunca" is Latin for cave) and explores them. 
Meaning of the word marked with <WSD> tags:  One who explores caves; one who spelunks, caver;  British English: potholer