pi
Some 10 letter P words:partialityparticularpermissionpersonallyprecautionpresupposepronouncedproportionprejudicedproportionprefermentprepaymentpreachmentplacementspracticingpercentileproductivepermissiveprovisionsprotectionprovention
procrastinate
preposterous
pepperoni
Primper.
phenomenal
There are no 23 letter words in the English language starting with the letter p.
prize
plaza
Plundering
pressed
Pepsi