One place where thelyphthoric is listed is in The Compact Edition of the Oxford English Dictionary (1971, Oxford University Press), which marks it as both obsolete and a nonce word. Two citations appear, from 1780 and 1794, I think.
From arcamax.com, where the word was featured as "Today's Word" on 3/6/05: Today's word was the creation of Martin Madan, who wrote in 1780 "Thelyphthora or, A treatise on female ruin: in its causes, effects, consequences, prevention, and remedy." Madan put this word together from Greek thelus "woman" + phthora "destruction, ruin." Both Greek words have resisted efforts of etymologists to dissipate their mystery.
I've seen 'thelyphthoric' listed in some specialized dictionaries of unusual words. It is listed on the site Luciferous Logolepsy and in Mrs. Byrne's Dictionary and Peter Bowler's _Superior Person's Book of Words_. The definition given is "that which corrupts women". The 'thely-' and 'phth' roots would be Greek, so the definition is feasible, but I've never seen it in any "official" dictionaries.