Numerous 4 letter words begin with the letter p. A few of those words include pace, pack, pact, pads, page, paid, pail, pain, pair, pale, palm, pane, pang, pans, pant, papa, pare, park, pars, part, pass, past, pate, path, pave, pawn, pays, peak, peal, pear, peas, peat, peck, peek, peel, peep, peer, pegs, pelt, pens, perk, perm, peso, pest, pets, pews, pier, pies, pigs, pike, pine, ping, pink, pins, pint, pipe, pits, pity, plan, play, plea, plod, plop, plow, ploy, plug, plum, plus, pods, poem, poet, poke, poky, pole, poll, polo, pomp, pond, pony, pool, poor, pope, pork, port, post, pots, pour, pout, pray, prep, prom, pros, pubs, puff, pull, pump, punk, punt, pure, push and putt.
Princess!
some words include:pabulumspachadompachalicpachinkopachisispachoulipachucospacifiedpacifierpacifiespacifismpacifistpackablea full list of words beginning with P containing 8 letters can be found here (see related links), although this list doesn't include every 8 letter word containing the letter P.
plans
people
Particle.
The silent letter in "mnemonic" is the "m" at the beginning of the word. In "pneumonia," the silent letter is the "p" at the beginning of the word.
8 letter words w/final letter P:raindropairstripback-flipbackdropsubgroupsidesteptownshipdoorstopbackstopworkshoplordshiphockshopteardropbookshoplollipoplockstepsidestepscrew-topoversteplong-jumpnightcappawnshopfiretrapfollowupbullwhipchange-upblacktopbakeshop
Another word for holy is pious.
peripheral
prow
presume
poignant