Okay, lest we miseducate fellow forum users, I have to report that I could not find the word in my new Webster's Unabridged Dictionary. I did find it in my older edition and it is listed only as an obsolete adjective meaning laborious, painful or painstaking (as in, "digging a ditch is a penible chore").

But since the dictionary evidently dropped it, I see no reason why it cannot be reborn as a noun with whatever meaning you want to give it.

Meanwhile, I would hesitate to use it in a Scrabble game.