pleuralgia vs. pleurodynia
papulovesicle vs. vesicopapule
paraesthesia vs. paresthesia
palsy vs. paralysis
prematureness vs. prematurity
paygrade vs. rating
prestige vs. prestigiousness
predicament vs. quandary
prosperity vs. successfulness
prolapse vs. prolapsus
polyvalence vs. polyvalency
polyethylene vs. polythene
phenylethylene vs. styrene
Teflon vs. polytetrafluoroethylene
plasticiser vs. plasticizer
protactinium vs. protoactinium
proenzyme vs. zymogen
pyrrhotine vs. pyrrhotite
progestin vs. progestogen
phenothiazine vs. thiodiphenylamine
parchment vs. sheepskin
polybutene vs. polybutylene
paperboard vs. posterboard
pyroxylin vs. pyroxyline
piddle vs. wanton
piddle vs. water
propanamide vs. proprionamide
polyurethan vs. polyurethane
podsol vs. podzol
polyose vs. polysaccharide
polypropene vs. polypropylene
propanal vs. propionaldehyde
propene vs. propylene
peptidase vs. protease
protease vs. proteinase
piperin vs. piperine
platelet vs. thrombocyte
pitchblende vs. uraninite
puberty vs. pubescence
playday vs. playtime
pollenate vs. pollinate
palliate vs. relieve
propagate vs. spread
propagate vs. wing
pule vs. whimper
pullulate vs. shoot
pullulate vs. stream
pullulate vs. swarm
perspire vs. sudate
ptyalize vs. spit
ptyalise vs. spit
parch vs. sear
petrify vs. rigidify
paralyse vs. paralyze
protrude vs. start
pare vs. trim
pare vs. skin
perturb vs. trouble
predate vs. raven
precede vs. predate
powderize vs. pulverise
powderize vs. pulverize
powderise vs. pulverise
powderise vs. pulverize
pulverize vs. ruin
pulverise vs. ruin
persevere vs. persist
persist vs. run
persist vs. stay
pressurize vs. supercharge
pressurise vs. supercharge
prepare vs. ready
prepare vs. train
provide vs. supply
purify vs. sublimate
perfuse vs. suffuse
popularise vs. vulgarize
popularise vs. vulgarise
popularize vs. vulgarize
popularize vs. vulgarise
prove vs. show
prove vs. raise
prove vs. rise
prove vs. test
presuppose vs. suppose
predestine vs. preordain
propose vs. suggest
personate vs. personify
phonate vs. vocalize
phonate vs. vocalise
prise vs. respect
provoke vs. stimulate
provoke vs. raise
pettifog vs. quibble
polemicise vs. polemize
polemicize vs. polemize
polemicise vs. polemise
polemicize vs. polemise
prohibit vs. veto
proscribe vs. veto
prevail vs. triumph
prevail vs. run
preach vs. prophesy
prophesy vs. vaticinate
proclaim vs. promulgate
prevaricate vs. tergiversate
palter vs. tergiversate
prologize vs. prologuise
prologize vs. prologuize
prologise vs. prologuise
prologise vs. prologuize
patronize vs. support
patronize vs. sponsor
patronize vs. shop
patronise vs. support
patronise vs. sponsor
patronise vs. shop
publish vs. release
publish vs. write
promote vs. raise
philander vs. womanize
philander vs. womanise
particularize vs. specialize
particularize vs. specialise
particularise vs. specialize
particularise vs. specialise
partake vs. touch
partake vs. share
procure vs. secure
patinate vs. patinise
patinate vs. patinize
pierce vs. thrust
preassemble vs. prefabricate
poetize vs. verse
poetise vs. verse
pester vs. tease
palpitate vs. quiver
pour vs. stream
prorogue vs. remit
penalise vs. punish
penalize vs. punish
pertain vs. touch
procrastinate vs. shillyshally
postpone vs. remit
quite vs. rather
quietly vs. softly
quiet vs. quietly
quietly vs. restfully
quickly vs. rapidly
quickly vs. speedily
quick vs. quickly
quick vs. spry
quick vs. warm
quick vs. straightaway
quick vs. speedy
quick vs. ready
quiet vs. tranquil
quiet vs. smooth
quiet vs. unruffled
quiet vs. still
quiet vs. subdued
quiet vs. restrained
quiet vs. repose
quiet vs. silence
quiet vs. tranquillity
quiet vs. tranquility
quiet vs. tranquillise
quiet vs. tranquilise
quiet vs. tranquilize
quiet vs. tranquillize
quiet vs. quieten
quiesce vs. quiet
questioningly vs. wonderingly
questioningly vs. quizzically
quadruped vs. quadrupedal
quadrangle vs. quadrilateral
quality vs. select
quality vs. timber
quelled vs. quenched
quelled vs. squelched
quenched vs. satisfied
quenched vs. slaked
qualified vs. restricted
questioning vs. quizzical
questioning vs. skeptical
questioning vs. sceptical
questionable vs. refutable
quizzical vs. teasing
quotable vs. repeatable
quenchless vs. unquenchable
quadruple vs. quartet
quadruple vs. quartette
quadruple vs. quadruplet
quaternary vs. quaternate
quintet vs. quintuple
quintette vs. quintuple
quintuple vs. quintuplet
quavering vs. tremulous