gruelling (adj.)
"to punish," from late 18c. slang get (or have) one's gruel "receive one's punishment," from gruel (n.).
Where does the word grueling come from?
Once upon a time in a land far far away (like eighteenth century England) there was an expression, to “get one's gruel,” which meant “receive one's punishment.” This saying morphed into the word grueling, which can be applied to any punishing activity.
What does the phrase gruel is insipid mean?
1 : a thin porridge. 2 [from to get one's gruel to accept punishment] chiefly British : punishment. 3 : something that lacks substance or significance the argument was thin gruel.
