First showed up in the 1570s when it was a common name for a plant. It didn’t emerge as a color until the seventeenth century. For the record, pinkie finger has nothing to do with the color. It’s actually from a Dutch word, pinkje, which means little finger. There’s also the pink that’s part of pinking shears, which isn’t related to pink or pinkie either.
This should surprise no one, but before it was a color, it was just the plant. It showed up in the early fourteenth century, and much like how orange the color derived from orange the fruit, violet comes from the flower.
Showed up in the mid-sixteenth century and shockingly enough, it comes from the Spanish inico, which itself comes from Dutch (indigo) by way of Portuguese (endego). Seriously, that’s how the word came to English. But of course Latin is involved, because indigo and endego come from the classical Latin indicum, taken from the Greek indikon. It literally means blue dye from India. The idea for the color comes from that dye.
This one is absolutely awesome. Teal was originally only a word for a species of small duck. Using it a color didn’t happen until 1923, where it was named for the blue-green colors on the bird’s head and wings.
Comes from the Old English tannian, a word for tanning hide into leather, which was done using tannin. Tannian comes from the Medieval Latin tannare, a word for the color tan which is derived from tannum, crushed oak bark.
First showed up as an adjective coming from the Old English brun, dusky, from the Proto Germanic brunaz and further back, the Proto Indo European bher, shining or brown. Yes, brown really did once mean shining. You know how burnish means to polish something? That has the same origin as brown.
TL;DR: most color names come from things that have the colors.
Ducks Unlimited because of course that’s a thing.
Tony Jebson’s page on the Origins of Old English