[ety. unknown. OED suggests SE pounce. Hancock, ‘Shelta and Polari’ (1984), notes Fr. argot pont (d’Avignon) or pontonnière, a prostitute (who works from the arches of a bridge); Partridge offers Fr. pensionnaire, a lodger and thus poss. link to earlier pensioner (at the petticoat) n. Note that many ‘ponce’ usages show the very different status of such a man in the UK compared with the US pimp]
[mid-19C+] one who lives off the earnings of one or more prostitutes.
[1930s+] a derog. epithet for any man or woman, incl. the police; the inference is of affectation and for men, effeminacy, if not actual homosexuality.
[1960s+] (Aus./US) a male homosexual.
[2000s] one who lives off beggars’ collections.