calthrop
personae, personal, plastics
Plankton
Some 10 letter P words:partialityparticularpermissionpersonallyprecautionpresupposepronouncedproportionprejudicedproportionprefermentprepaymentpreachmentplacementspracticingpercentileproductivepermissiveprovisionsprotectionprovention
preposterous
procrastinate
pi
phenomenal
Primper.
pepperoni
There are no 23 letter words in the English language starting with the letter p.
prize