One way to hold this word: a man who does not put anything in. What he needs comes off someone else, and what he does with his time is make a show of himself. British slang built two lines out of that one figure, and every use of the word is said with contempt.
Wiktionary says the origin is uncertain, but probably an aphetic form of French alphonse, a kept man, with pounce and French pensionnaire also suggested. If the alphonse route is right, the kept-man sense is the oldest part of the picture.
Wiktionary 說這個字來源不確定，但很可能是法文 alphonse（被女人養的男人）縮掉字頭而來，也有人提出 pounce 或法文 pensionnaire。若 alphonse 這條線正確，那麼「靠別人養的男人」就是最早的那一塊，其他用法都是從它長出來的。這裡的不確定是來源本身標註的，不是我們的推測。
Wiktionary entry for ponce, etymology 1 (packet evidence kaikki:3f6f69a190036ae4:622313755): Uncertain, but probably an aphetic form of French alphonse (kept man).
Two branches
錢從別人身上來
這一支最貼近可能的字源 alphonse：自己不賺，錢從別人身上拿。動詞把同一件事縮小到日常小東西。
noun · C1
British slang for a man who lives on money that someone else earns, especially a woman. It is used in particular for a man who controls a woman who sells sex and takes her money, which American English calls a pimp.
靠別人養的男人；皮條客
被嘲笑的那個樣子
同一個人物，看的角度換成外表和舉止：愛打扮、愛做樣子，於是被拿來當侮辱語，動詞再把那個樣子變成動作。
noun · C1
A British slang insult for a man, used because people think he dresses or behaves like a woman, or because they think he is gay. It is a strong insult and Longman marks it taboo, so it is a word to understand when you read or hear it rather than one to use.
（冒犯語）娘娘腔的男人