You can't read a book or watch a movie about the seafaring life without running into the word landlubber. Maybe you've heard a definition of the word, or maybe you just inferred the definition from the context.
"Captain Jones, Governor Williams' son wants to join our crew."
"Ah, that there's a family of landlubbers; the boy won't know the difference between a rudder and galley."
From this you infer, correctly, that a landlubber is someone who doesn't know much about life aboard a ship. And, since the word is a compound word made up of land and lubber, you might infer -- also correctly -- that a landlubber is someone who has spent their whole life on land, and (in the eyes of the seafarers) should probably stay there.
But you might have gone a step further in your inferences and wondered, "What in the world is a lubber? Is that even a word?"
It is a word. And I thought I knew what it meant. You see, I've spent some time in South America, and was fascinated to notice that the letter B and the letter V are pronounced the same. "Oh!" I thought, "lubber is just a misspelling of lover! So a landlubber is someone who loves the land instead of the sea."
As I said, I thought I knew. It turns out I was completely wrong about the origin of the word.
Lubber is believed to come from an Old French word: lobeor. What did the word lobeor mean? A lobeor was a cheater or a swindler.
That knowledge puts a whole different twist on the meaning of the word landlubber. When Captain Jones called the Williams family a family of landlubbers, he wasn't just saying that they don't know anything about the seafaring life; he was also saying that, because they were not seafarers, they weren't to be trusted!
Nowadays, the word no longer carries that meaning. It simply means "a person unfamiliar with the sea or sailing." And the word lubber, by itself, means "a big, clumsy person." But there was a time when it was simply a way of saying, in effect, "You're not like us, so we don't trust you."
Sounds like our world today.