odious and oppressive

offensive and aggressive

official and authoritative

oily and servile

old and decrepit

ominous and untrustworthy

omnivorous and sordid

oneness and unity

onerous and perplexing

open and inviting

opinions and hypotheses

opportunism and inconsistency

opposite and discordant

oppressed and sullen

optimistic and reassuring

opulence and magnitude

oracular and occult [oracular = solemnly prophetic; obscure]

order and uniformity

organic and rational

organization and system

origin and discovery

original and attractive

ornate and variegated

ostensible and explicit

ostentatiousness and gaiety

outlines and appearances

outrageous and scandalous

overburdened and confused

overcome and vanquish

overstep and contravene

overt and unmistakable

overwearied and outworn

overworked and fagged [fagged = worked to exhaustion]

P

pains and penalties

painstaking and cumbersome

pale and anxious

palpable and plain

paltry and inglorious

pampered and petted

parade and display

parched and dry

partial and provisional

particularly and individually

parties and sects

passion and prejudice

passive and indifferent

pastimes and diversions

patent and pertinent

pathos and terror

patience and perseverance

patriotism and reverence

pattern and exemplar [exemplar = worthy of imitation]

peaks and pinnacles

pedagogue and pedant
             [pedant = exhibits learning or scholarship ostentatiously]

pedantries and affectations

pedigree and genealogy

peevishness and spleen

pellucid and crystal [pellucid = transparently clear]

penetrating and insidious

penned and planned

peppery and impetuous

perception and recognition

peremptorily and irrevocably [peremptorily = not allowing contradiction]

perilous and shifting

permanent and unchangeable

permeate and purify

pernicious and malign

perplexity and confusion

persistent and reiterated

personal and specific

perspicuous and flowing [perspicuous = clearly expressed]

perturbed and restless

perverted and prejudicial

pessimistic and disenchanted

pestilence and famine