Warning up front: This alphabet is not safe for work and not intended for kids!
Normally, the alphabets that I find are aimed at young children and maybe their parents and teachers. They may be quirky or use word choices intended to amuse the adults as much as the children, but kids are always the front and center intended audience.
That’s not always the case, though! Probably the earliest completely “adult” alphabet that I have found is a series of art prints by French artist Joseph Apoux titled Alphabet pornographique which was published in 1880. A clear, blocky rendition of the letter is present in each piece, but frolicking before it and clearly spelling out the letter with body positions are people in various states of undress performing various sexual acts.
I chose probably the most innocent one to share here, just in case someone was to open the post somewhere they shouldn’t, but trust me – there are some great ones. This is the letter I of course, which is simply portrayed by a woman exposing her body to the viewer demurely. There aren’t actually words associated with each letter, as far as I know, but this one feels like a beautiful illustration of an intimate moment to me, so that’s the word I chose for it. I found that finding the right word for each letter was actually kind of a fun exercise!
If you want to see the whole alphabet (and I do recommend it – there are some absolutely gorgeous details throughout and it’s quirky enough to be worth the experience), you can find it at Flashback in a post about the whole series of prints. Be warned that there are all sorts of couples and groupings of Victorian aristocrats doing all kinds of interesting things to form letters (and a few clergy members thrown in, because if you are going to make taboo, underground art, why not go that extra step?).