Webster's Revised Unabridged Dictionary · 1913

Punctilious

Punctilious (-yus) , adjective

[Compare Italian puntiglioso, Sp. puntilloso.]

Attentive to punctilio; very nice or exact in the forms of behavior, etiquette, or mutual intercourse; precise; exact in the smallest particulars.
A punctilious observance of divine laws. — Rogers
Very punctilious copies of any letters. — The Nation
Punctilious in the simple and intelligible instances of common life. — I. Taylor