Some words beginning with P and ending with K:
packparkpeckpeekpeakperkpickporkpockpunkpuck
park, punk, pick, prank, pack, pork, pink, peacock, plank
The curse word that starts with "p" and ends in "k" is likely "prick."
atop
peacock
pizzazz.
Pies
pill
pill pencil
prohibiter
bookshop
pedophile