- Ps and Qs
- Packed to the gunwales
- Paddle your own canoe
- Paint the town red
- Panic stations
- Paper tiger
- Pardon my French
- Parting shot / Parthian shot
- Pass muster
- Pass over to the other side
- Pass the buck
- Paying guest – A
- P.D.Q. – pretty damn quick
- Pearls before swine
- Pears for your heirs
- Pecking order
- Peeping Tom
- Peg out
- Pell-mell
- pen is mightier than the sword
- Pennies from heaven
- Penny dreadful
- penny drops
- Penny pinching
- Penny for the guy
- Penny for your thoughts
- Penny saved is a penny earned
- Penny wise and pound foolish
- Pester power
- Peter out
- Petty cash
- Phrases and sayings quiz
- Phrases that people get wrong
- Physician heal thyself
- Pick 'n' mix
- Picture is worth a thousand words
- Picture-perfect
- Pie
- Pie in the sky
- Piece of cake
- Piece of p***
- Piece of the action
- Pig and whistle
- Pig in a poke
- Pigeon-chested
- Pig's back
- Pig's ear
- pig's eye
- Piggyback
- Piggy-wiggy
- Pigs might fly
- Pin money
- pinch of salt
- Pip
- Pipe down
- Pipe dream
- Piping hot
- P*** and vinegar
- Pitch black
- Pitch dark
- Pits
- Place for everything and everything in its place
- Plague on both your houses
- Plain sailing
- Plates of meat
- Play by ear
- Play Devil's advocate
- Play ducks and drakes
- Play fast and loose
- Play gooseberry
- Play it again Sam
- Play second fiddle
- Play silly buggers
- Play the giddy goat
- Play the race card
- Pleased as Punch
- Plug-ugly
- Plugged nickel
- Poetic justice
- Point-and-click
- Point-blank range
- Point Percy at the porcelain
- Point to point
- Politically correct
- Pommy bashing
- Pomp and circumstance
- Pond life
- Pony and trap
- Pony up
- Pop goes the weasel
- Pop your clogs
- Popular fallacies
- Pork pies
- POSH – Port out, starboard home
- Pot calling the kettle black
- potluck
- Pound of flesh
- Pour oil on troubled waters
- Power corrupts; absolute power corrupts absolutely
- Power dressing
- Powers that be
- Praying at the porcelain altar
- Preaching to the choir
- Prepositional phrases
- Preposterous
- 'Preposterous' phrases
- Press into service
- Presto chango
- Pretty kettle of fish
- Pretty penny
- Prick up your ears
- Pride comes before a fall
- Prime time
- Primrose path
- Problem shared is a problem halved
- Procrastination is the thief of time
- Proof of the pudding is in the eating
- Proverbs
- Pull in your horns
- Pull out all the stops
- Pull the other one, it's got bells on
- Pull the wool over your eyes
- Pull up stakes
- Pull your finger out
- Pull your horns in
- Pull yourself up by your bootstraps
- Pulling one's leg
- Punch above one's weight
- Pure as the driven snow
- Purple patch
- Push the boat out
- Push the envelope
- Put a damper on
- Put a sock in it
- Put a spanner in the works
- Put on the wooden overcoat
- Put on your thinking cap
- Put paid to
- Put the cart before the horse
- Put the mockers on
- Put the wood in the hole
- Put up your dukes
- Put your back up
- Put your best foot forward
- Put your nose out of joint
- Put your oar in
- Put your shoulder to the wheel
- Pyrric victory