orange
The color orange is first used as a color word in 1502 by analogy with the fruit, like with indigo and olive. The fruit, in turn, is first described in English as orenge in the late 1300s, named after the French term “pome orenge”, which went on a journey through Italian “arancia”, Arabic “نارنج” (nāranj), and Persian “نارنگ” (nārang), finally originating with Sanskrit “नारङ्ग” (nāraṅga) around the tree’s original range in northern India.
Usages from 1502 through the early 1600s all say “orange-coloured”, eventually dropping the second word once it became implicit that orange was a real, proper color word. So wait, what was the English word for that color all that time before anyone speaking it knew what an orange was?
It looks like it displaced several other words. Often it was called the equivalent of “yellow-red”, ġeolurēad, like we sometimes say “blue-green” today for cyan or teal. Sometimes it was referred to using other similarly-colored things like saffron or citrine. In heraldry the color was called tawny. Finally, it was sometimes just called “red”, which had a wider definition back then. Elements of this can still be seen in things that are still referred to as “red” even though they are clearly orange, like “redhead”, “red-breasted robin”, or Mars being the “red planet”.
weeb
The word weeaboo first appears as a nonsense word in a 2005 Perry Bible Fellowship webcomic: https://pbfcomics.com/comics/weeaboo/
It gained its current meaning later that year. On anonymous web forum 4chan, “wapanese” was then a common slur used against white people who enjoyed anime and manga. As an intervention, moderators added a word filter that replaced all instances of it with a ridiculous word that didn’t mean anything, “weeaboo”. This did not dramatically reduce the frequency of its usage, but it did end up changing the word that was used.
Weeaboo continued to be a common enough word on the internet that a short form, weeb, became standard within a few more years. It has mostly lost its original pejorative sense.
hello
The greeting hello is first found in print (spelled “hulloa”) in a 1878 Connecticut phone directory. Before becoming the default English phone greeting word, it was used in the American West as a nonsense shout to get attention, as early as 1826. It’s likely related to similar attention-getting English shouts, probably descending from “Hey! Lo!” over a thousand years ago.
Notably, Alexander Graham Bell preferred the use of a different specialist greeting word, the nautical ahoy, when answering the phone. His reasoning was similar to “hello” - it was an existing word that wasn’t widely used and was easy to distinguish from any other word, like how Alexa or Siri were decided on as wakewords more recently. In a recurring theme, “hello” had Edison’s support and eventually won out, although the deciding factor was probably early phone etiquette guides recommending its use. Bell continued to answer the phone with “ahoy” until his death.
You may notice just how path-dependent this development is. In particular, early phone etiquette developing differently in different countries can be a fun mirror into alternate realities. For example, Mexican Spanish uses ¿Bueno? as shorthand for “Is the connection good?” while Spain Spanish uses ¿Diga? meaning “Yes, speak?”
werewolf
The word werewolf predates English, which means it was first used some time before the year 400. It’s a compound of wer-, meaning “male person”, and -wolf, meaning “wolf”. Basically just “Man-Wolf” (1962, DC Comics) or “The Wolf Man” (1941, Universal Pictures), except using what was then the word for “man”.
Notably, wer used to be the English word for “husband” before husband took over its meaning around 1300, a revelation if, like me, you ever wondered why it looks so different from “wife”. A married couple were wer and wyf before then. The Latin equivalent is vir-, like in virile.
Today, were- is a productive prefix in English, yielding gems like weretiger, which can be used without any consideration to the weretiger’s gender.
nerdsnipe
The term nerdsnipe originates from a 2007 xkcd webcomic, perhaps inspired by a real-life anecdote from John Conway, the inventor of Conway’s Game of Life. As with all xkcd webcomics, additional background information can be found at its associated explainxkcd article: https://www.explainxkcd.com/wiki/index.php/356:_Nerd_Sniping
One thing I appreciate about the term is that it’s a microcosm of how English compound words are created. In the originating comic it’s spelled “nerd snipe”. Three years later, the same author spells it “nerd-snipe”. I don’t have a good date on the unhyphenated version, but I can see that I was using the spelling “nerdsnipe” by at least 2018. One interesting point of comparison is when news outlets and style guides started dropping the hyphen in “email”, and extrapolating that most people probably started dropping it a few years before that.