ŝvebi

Hovering, not floating. The nearest word on the site is flosi, and the two are not interchangeable. Flosi is to float on the surface of a liquid: a raft, a leaf on a pond, a body of water holding something up. Ŝvebi is to hang in the air or in a fluid without support and without going anywhere - a kestrel over a verge, dust in a sunbeam, mist between trees. If something rests on a surface, it flosas. If nothing is holding it up and it stays put anyway, it ŝvebas.

Against flugi. Flugi is to fly, and flying implies travel. Ŝvebi deliberately does not: the whole point of the word is that the motion has stopped while the height has not. That is why a glider ŝvebas and an aeroplane flugas, and why ŝvebi is the verb for a hawk holding station in a headwind.

The figurative use is the common one in prose. A question, a threat, a smell or a mood ŝvebas over a room, exactly as English says it hangs in the air. Ŝvebi inter vivo kaj morto is to hang between life and death, and it is standard. The adverbial participle ŝvebante does a lot of quiet work in narration - ŝvebante super la akvo - and the noun ŝvebo names the state itself.