punctilious
punk-TIL-ee-usadjMeaning very careful to follow the exact rules of proper behavior
Memory hook PUNCT: every POINT of manners. Professor Edwin bows just so, pours the tea just so and sets each spoon just so: every small point of manners is right. He is punctilious.
The punctilious host greeted every guest by name and seated each one by the place card.
In context Grandpa Gus is punctilious about manners: he stands when a guest comes in, writes a note for every gift and never starts eating before the cook sits down.
Similar proper, exact, formal, scrupulous
Opposite casual, careless, lax
From punctilio, a fine point of manners, from Italian puntiglio and Spanish puntillo, “a small point,” from Latin punctum, “point.”