Greetings fellow Earthlings and anyone else who might be reading this. Did you know that this word originally meant farmer?

These days in Science Fiction, an Earthling is “an inhabitant of Earth, as opposed to one of another planet; specifically, a sentient member of any species native to Earth.”

In the 17th century is referred to “A person who is materialistic or worldly; a worldling.” and in the 16th century, it referred to “An inhabitant of Earth, as opposed to one of heaven.” [source]

Going back further, it meant one who tills the earth, a farmer, a husbandman or a ploughman. It comes from Middle English erthling (farmer, ploughman), from Old English ierþling, eorþling (farmer, husbandman, ploughman), from eorþe (ground, dirt, planet Earth), from PIE *h₁er- (earth) [source]

Other interesting words suffixed with -ling include:

• puffling = a young puffin
• princeling = a minor or unimportant prince
• sportling = a little person or creature engaged in sports or in play
• shaveling = someone with all or part of their head shaved, notably a tonsured clergyman; a priest or monk (often derogatory).
• wildling = a wild plant or animal
• witling = a person who feigns wit, pretending or aspiring to be witty, a person with very little wit.
• godling = a young god, a minor divinity, a local or inferior god, a.k.a. godlet, godkin

There’s also underling (a subordinate or person of lesser rank or authority), and it’s rare antonym overling (a superior, ruler, master) [source]

You can see more of these on: https://en.wiktionary.org/wiki/-ling#English