Megrim – what a perfectly descriptive word. I mean, me + grim = headache. It’s also one of those words that just sounds nice in it’s descriptive nature. I know I’d much rather say that I’m suffering from a bit of a megrim today, due, no doubt, to this changeable weather, instead of, ugh, I’ve got another migraine. Perhaps that’s the ‘fancy’ of it, tee-hee. I can actually see where the whim or fancy part of the definition of megrim comes from since a headache can be brought on by so many things, some of which are at a whim or caused by a flight of fancy, just in my option, mind. Megrims can also cause quite low spirits, especially if they stick around and cause undue suffering in the form of nausea, sensory sensitivity (think light, sound, smell, etc.) and just general unpleasantness. Just ask anyone who has ever had a megrim and they will tell you that it is hell, though being able to use the word megrim to describe it is a very small sort of consolation…at least for me it is (I’m delightfully weird like that).
Here’s hoping that today’s megrim doesn’t last!
Namaste ~ Ella
*Check out the Word Nerd Index and the Word Nerd Pinterest Board for further logophile reading!
* If anyone has a suggestion for future Word Nerd entries, please feel free to leave a note (or word) in the comments!
Lawhimsy 
I can see where the word comes in to play with its definition of flight of fancy or whim. Like you pointed out me-grim: many of us seem to bring on our own low spirits that can develop into depression as well as physical illness (headache). How we take things and/or make them out and the results they have can be megrim indeed! Now I wonder if there’s a mehappy…;)
I’m sure there simply has to be…hmmmmm, I sense a future Word Nerd possibility!