1. [late 16C+] syphilis.
2. [18C–19C] brandy.
3. [late 19C+] taboo language.
4. [1910s+] (also French art, full French) fellatio (cf. Frenching n.).
5. [1970s] pornography.
[late 19C+] a genteel euph. automatically offered after the speaker has sworn in public.
[17C] to become infected with syphilis.
[20C+] to indulge in unconventional sexual play.
[1940s] (US) to fellate.