Originally used in the sense of defeat or frustrate. The word itself, containing with the prefix con (meaning “not”—well, sometimes) and fuse (meaning “not pull apart”—as in “Martha always seems to be fused to whatever book she’s reading”), has a major flaw: It sounds like it should be a synonym of scatter, not befuddle. (Although, the two concepts are related, so it’s not that large a gulf in meaning.)
On the other hand, in it’s “confusion” form, the vowels have a lovely, almost musical rhythm: Con‑fus‑ion. Uh‑oo‑uh. Merely uttering this word puts a dab of chaos into the world, a momentary sense of spontaneity that allows one to almost picture a level-headed person morphing into a scatterbrained entity.
I highly recommend this word to satisfied users of the words “fusion” and “concision”. (If you didn’t like “dimension” and “emission”, don’t waste your time here.)
Short words often imply that something is quick, or small, or unimportant.
Pip. Trip. Stop.
This word, with its clipped syllables, pounds the point into the cold, hard ground. The imperceptible thing is not so much an unimportant thing as an unnoticeable thing. In a meta sort of way, the difference between varying states of the thing is hard to make out. While a cloaked Romulan ship (say) might be imperceptible, this word usually means that a change is so small, so gradual, as to be difficult to notice.
Imagine a thief who steals one thing a day from your home, and still can’t find where Waldo is hiding amidst your piles of dusty murder-mystery paperbacks. Books that are all different—somehow. At what point do you notice the change?