A word that's puzzling me

A word puzzled me earlier, while I was trying to write the first three sentences of a new work. ‘Thine heart is the essence of humanity,’ read the text. John sighed. Another murder to remain unsolved.

The opposite of solvable is spelled how exactly? I couldn't find the correct spelling of it in MS Word nor in a dictionary/theasaurus.

What I wanted to say was:

‘Thine heart is the essence of humanity,' read the text. John sighed. Another murder, another unsolvable one. (I know there could be an e in there however after the v. But the processor didn't accept either version.)

I know the other variation it could be is insolvable. Anyway, I'm a bit perplexed. Google isn't much help either and I'll probably settle on the first example now, but still, I'm just curious.

 

Insolvable is correct, according to dictionary.com, but you can also consider insoluble.

 

Alright, thanks a lot Cogito. It just generally confused me and anyone I asked didn't know. I'll keep dictionary.com in mind, for the future. I had no idea about that website. I'd just used google to search for it on the net and it turned up results that weren't pertinant to what I wanted to know.

Curiosity was the main reason I asked. You know, you don't know something and you need to know? Or else, it drives you insane.

 

Too late, in my case. Nhahaha. hee hee. Haw haw haw - ngh? gulp.

 

'insolvable' grates on my reader's nerves... the more common 'insoluble' feels much better to this aged person who'd never seen/heard the former term in her youth... or since, as a matter of fact...

 

I'm with you on that, Maia. Although I suspect the character might find "unsolvable" a more natural word to use, lbeit not entirely proper. So if this is a literal thought, color may win out over correctness.

 

Hey, thanks for the continued input. I also thought of insoluble. It was at least, the most correct word I could get the processor to accept. I agree as well, it sounds better. A good point though regarding which word the character would use.

And Cogito, I think I'd have a field day trying to decipher what you said further up.

(I've settled on the phrase to use now by the way.. However, I may rephrase the sentence in question to fit with insoluble.)