Used mainly attributively before nouns (e.g., "pier lighting"); it is not normally graded, so comparative and superlative forms are not standard.
Definitionen
Relating to, situated at, or suitable for a pier. The city installed new pier lighting to improve safety at night.
Used attributively or informally in British English meaning self-righteously pious.
Definitionen
(British informal) Self-righteously or smugly pious. He adopted a rather pi attitude, lecturing everyone on morality.