1. In an extreme or otherwise remarkable manner, as of one's behavior. Boy, the kids are in rare form today—how much sugar did you give them? Patty always seems so timid, but she was in rare form in the meeting and deftly answered all of the board members' questions.

What does it mean to say in rare form?

DEFINITIONS1. behaving or performing in a way that is especially clever, skilful, amusing etc. Toronto's outrageous mayor was in rare form during his speech last night.

Where does the term rare form come from?

Rare comes from the Latin word rarus, meaning “widely spaced,” as rare things are — whether in actual space or in time. You thought it was rare to meet someone you have so much in common with, until he fainted looking at the rare steak you ordered.