| Prorate, Proprietorship, Proprietor | |
| Prospect, Prospectus, Prosperity |
Arguments or considerations for and against something, as in We'd best weigh all the pros and cons before we decide to add a new wing to the library. This idiom is taken from the Latin pro for "for" and con for "against." [Late 1500s]
Proficiency and conduct marks given to Marines to the rank of sergeant by their supervisors. They are part of the formula used for promotion. Each is between 0 (totally unsat, probably not breathing) and 4 (God, on a good day).