Premier vs. Premiere
Prescribe vs. Proscribe
Principle vs. Principal
Prophecy vs. Prophesy
Prostate vs. Prostrate
Quell vs. Quench
Quiet vs. Quit
Quotation vs. Quote
Race vs. Ethnicity
Rack vs. Wrack
Rain vs. Reign
Raze vs. Raise
Rapt vs. Wrapped
Rational vs. Rationale
Ravage vs. Ravish
Recourse vs. Resource
Regretful vs. Regrettable
Reluctant vs. Reticent
Respectfully vs. Respectively
Restive vs. Restless