NATIONAL

a/the national flag

a/the national government

a national holiday

a national monument

a national park

national consumption

national pride

national reconstruction

national service

a/the national anthem

a national assembly

NATURAL

a natural disaster

natural resources

natural childbirth

natural gas

natural history

natural selection

the natural environment

NAUTICAL

a nautical mile

NEAR

a near miss

the near future

NEIGHBORING

NERVOUS

a nervous breakdown

a nervous disorder

a nervous wreck

nervous exhaustion

NEW

a new car

a new idea

a new look

a new moon

NEXT

next door

next month

next summer

next week

next year

NON-PERFORMING

a non-performing loan

NOMADIC

a nomadic lifestyle

NON-STOP

a non-stop flight

NON-VERBAL

non-verbal communication

NORMAL

NORTH

North American

North Korea

the North Pole

the North Star

NORTHERN

northern Australia

the northern hemisphere

Northern Ireland

NOTED

a noted authority

NOTIONAL

NUCLEAR

nuclear power

a nuclear family

a nuclear reactor

a nuclear war

a nuclear warhead

a nuclear winter

nuclear energy

nuclear fission

nuclear fusion

nuclear non-proliferation

nuclear warfare

nuclear waste

NUMERICAL

NURSING

a nursing mother

NUMEROUS

numerous tests

OBJECTIVE

an objective viewpoint

OBSERVATIONAL

OBSERVED

OCCASIONAL

an occupational hazard 

occupational therapy 

OCCUPIED

occupied territory

OCEAN-GOING

an ocean-going liner

OFFICIAL

an official announcement

OLD

old age

“an old flame”

“an old hand”

an old man

an old woman

an old master

OLYMPIC

The Olympic Games

OPEN

the open air

an open door

an open invitation

an open letter

an open mind

an open prison

an open question

an open secret

an open sesame

an open verdict

open access

open arms

open water

the Open University

Exceptions:

open day    (contrast stress; Type 1 - a type of day)

open season   (contrast stress; Type 1 - a type of season)

OPPOSITE

somebody's opposite number

the opposite viewpoint

the opposite building

OPTICAL

an optical illusion

OPTIMUM

OPTIMISTIC

OPTIONAL

OPULENT

an opulent lifestyle

ORAL

oral hygiene

oral history

ORCHESTRAL

ORGANIZED

organized crime

ORIGINAL

an original idea

ORNAMENTAL

OUTDOOR

an outdoor swimming pool

OUTER

outer space

OUTGOING

OUTSTANDING

an outstanding performance

an outstanding talent

outstanding ability

outstanding cinematography

OVERBEARING

an overbearing manner

OVERDRAWN

an overdrawn account

OVERHEAD

an overhead projector

an overhead railway

OVERSEAS

overseas study

OVERWHELMING

PAID

a paid holiday

PAINTED

PARALLEL

parallel parking

parallel processing

PARKED

a parked car

PARTIAL

a partial eclipse

a partial payment

PARTICULAR

PART-TIME

a part-time job

PAST

PATERNAL

my paternal grandfather

PEAK

peak oil

PEELED

a peeled banana

PENETRATING

a penetrating analysis

PERFECT

a perfect fit

a perfect match

a perfect score

perfect pitch

a/the "perfect storm"

PERFORMING

a performing bear

the performing arts

PERIODIC

the periodic table (in chemistry)

PERIPHERAL

peripheral vision

PERSIAN

a Persian cat

PERSONAL

a personal ad

a personal allowance

a personal assistant

a personal attack

a personal ad

a personal computer

a personal identification number (PIN)

a personal organizer

a personal pronoun

a personal trainer

personal effects

personal property

a personal video recorder (the noun is Type 1, "video recorder")

PESSIMISTIC

a pessimistic outlook

PHILOSOPHICAL

a philosophical discussion

PHRASAL

a phrasal verb

PHYSICAL

physical attraction

physical education (= P.E.)

physical fitness

PHYSIOLOGICAL

PICTURESQUE

a picturesque view

PIPED

piped music

PITCHED

a pitched battle

PLAIN

plain sailing

PLASTIC

plastic surgery

POACHED

a poached egg

POETIC

poetic justice

poetic licence (American spelling is "license")

POLAR

a polar bear

the polar ice-cap

POLISHED

a polished performance

POLITE

polite conversation

polite society

a polite request

POLITICAL

political correctness

Political Science

a political prisoner

POOR

poor quality

"Poor thing"

POPULAR

the popular press

POSITIVE

a positive example

a positive outlook

positive discrimination

POTENTIAL

a potential leader

potential energy

PRACTICAL

practical results

a practical idea

a practical joke

PRECIOUS

a precious metal

(a) precious stone

PRECISE

a precise measurement

PREGNANT

a pregnant silence

a pregnant woman

PREPARED

a prepared answer

PRESIDENTIAL

the presidential palace

PRESIDING

a/the presiding officer

PRESSING

a pressing engagement

PRETTY (1)

a pretty dress

a pretty girl

PRETTY (2)

Note: the second word here is an adjective: the word "pretty" here is an adverb that modifies an adjective.

pretty bad

pretty cheap

pretty funny

pretty good

pretty new

pretty old

pretty young

PREVAILING

the prevailing wind

PRIME

a prime cut

a prime number

a Prime Minister

prime time

a prime mover

the prime rate

PRINCIPAL

the principle part(s)

PRIVATE

private enterprise

private tuition

a private company

a private detective = a private eye

a private secretary

PROBLEMATIC(AL)

PROCESSED

processed food

PROFESSIONAL

a professional musician

a professional tennis player

professional wrestling

professional development

PROGRAMMED

programmed instruction

PROMISING

a promising future

PROPORTIONAL

proportional representation

a proportional split

PROTECTED

a protected species

PSYCHOLOGICAL

psychological damage

psychological warfare

PUBLIC

public affairs

a public body

a public performance

public funds

public relations

public transport

public transportation

public works

a public convenience

a public company

a public library

a public servant

public speaking

PURE

pure gold

pure silk

pure chance

PUZZLED

a puzzled expression