Where does the word 'Shrove' come from?

"Shrove" is the past tense of "shrive", meaning "to hear a confession".

It is most common in the term "Shrove Tuesday" referring to the fact that Catholics would seek absolution of sins prior to the beginning of Lent.

"Shrive" comes from the Old English "scrifan", which was used to mean "prescribing or recommending a confession". This is ultimately from the Latin "scribo", meaning "to write" (as in "prescribe", "scribe", "scribble", "script").

The noun form is "shrift". If you're convicted of a capital offense, you get a "short shrift" prior to your execution. If your buddies have taken the loot, and you "get the short shrift", then you've been badly cheated.