Perhaps it's dated too: I came across it in one of the books of the 'Jeeves & Wooster' series by PG Wodehouse: "Right-Ho Jeeves", Chapter 7, Page 56, line 2 (Penguin Books, 1973 edition).And it is so rare that I had not met it before. :shock:
I think you have misinterpreted my suggestion. Wodehouse did not use words which could directly suggest anything derogatory in the picture he was drawing and therefore effeminate does not appear in his books; using oofy for poofy is the sort of allegory that he regularly employed.As a footnote to Vil's comprehensive explanation: "oof" ("money", from which "oofy" derives) is first recorded for 1885. An "oof-bird" is a supplier of money; one may be "oofy" or "oofless".
Wodehouse is a repository of outmoded slang from the early part of the 20th century. It is very difficult to tell which words are his own coinages, and which were genuinely used. (I would be quite surprised to find an implication of "poofy" behind his use of the word, as his characters generally cease to exist at about the midriff, and only resume just above the knee.)