hmm... it's a little hard to explain this. this word describes a kind of bad state of someone. for example, Tom is a young man who is very very good at tennis. He believes that he is the best in the world. but one day, he loses to someone. from then on, he stops playing tennis. because when u touch the tennis racket, he gonna be tormented by his memory about losing that game. now we can say: Tom 沉倫于失败。 沉倫 is a verb. it means deep in, drown in it is always followed by a bad word, such as 失败（failure），疾病（sick） it means someone is suffering something bad and cant get rid of it. i hope u could get it.

Chinese undergrads often use it to mean "I am drowning in youthful hedonism - not working hard enough, playing too much..." You could say "Drug addicts 沉沦于毒海中。"

See this link for a non-communist view: http://zh.m.wikipedia.org/zh-hk/%E6%B2%89%E6%B2%A6_%28%E9%83%81%E8%BE%BE%E5%A4%AB%29

沉沦is also a well-known novella by 郁达夫。 See this introduction: http://wapbaike.baidu.com/view/117303.htm?adapt=1&

It means "drowning; sinking to destruction". Even many Chinese people misunderstand and misuse it. See this link to a good scholarly explanation in traditional characters. http://dict.revised.moe.edu.tw/cgi-bin/newDict/dict.sh?cond=%A8I%B2_&pieceLen=50&fld=1&cat=&ukey=699040441&op=&imgFont=1