presto maturo, presto marcio (It.) Soon ripe, soon rotten.

pretium laborum non vile (L) The value of labor (is) not trifling. (黄金羊毛勲爵士団 (the Order of the Golden Fleece) のモットー)

principia, non homines (L) principles, not men.

principiis obsta (L) Resist the first beginnings.　― Ovid, Remedia Amoris 91 (cf. venienti occurrite…).

prior tempore, prior jure (L) First in time, first by right; first come first served.

pristinae virtutis memores (L) mindful of the valor of former days　― Sallust, Catilina 60.