Here's the twist: "buoyant" didn't form in English the tidy way most people assume — buoy plus the suffix "-ant." It actually sailed in from Spanish. The word takes a scenic route to get here: it's built from Spanish boyante — the present participle of boyar, meaning "to float" — which itself grew out of boya, the Spanish word for buoy. Spanish, in turn, is thought to have picked up boya from Dutch boei. English adopted the finished word, roots and all, in the 1570s.

The noun "buoy" had already been floating around English on its own since the late 1200s, and its ancestry is still debated: some etymologists trace it to a Proto-Germanic word for "beacon" (the same root that gives us "beacon" itself), while others argue for an Old French or Middle Dutch word meaning "fetter" or "chain" — the theory being that early buoys were literally objects chained in place to mark a fixed spot in the water. Either way, it took nearly two centuries after "buoy" arrived for the cheerful, good-mood sense of "buoyant" to show up, around 1748 — this word apparently needed some time to learn how to lift moods, not just boats.

Every good story needs an ending. The next word is the one that ties up every loose thread and brings the whole tale to its close.