What it means: to submerge; to cover completely; to surge over
From ME. welmen (or whelmen), perhaps a merging of OE hwelfan “to cast down” and helmian “to cover.” The cognate helm, of course, is the wheel or tiller to steer a ship; the use of whelm may have begun to describe the sinking of a ship.
Why I chose it: We use the word overwhelm pretty regularly. Why not just whelm? Seems like overkill to me (which is overkill for kill itself, ’cause let’s face it, once something is dead, it’s tough to kill it some more). I thought about this word because, well, I’m feeling a bit whelmed. It’s a busy time, which is a very good thing! But I’m getting a little tired and need to catch up on sleep. You could say I’ve got that sinking feeling… 😉