Antonyms

Barbarous is primitive/ uncivilised. So, opposite is civilised.

Decorous means decent looking, seemly. Its opposite is unseemly.

Pathological means unhealthy. Its opposite, among the choices, is normal.

Perennial means everlasting; eternal. Its opposite is fleeting, meaning short-lived; ephemeral; momentary; fleeting.

The opposite of pellucid, among the choices for this question, is opaque.

Perfidy means treachery; betrayal; disloyalty. Its opposite is loyalty.

Pedestrian means commonplace; uninteresting. Its opposite is imaginative, meaning artistic; inspired.

Pellucid means clear; transparent. Its opposite is turbid, means misty; foggy.

Peripatetic means wandering; foot-loose; nomadic. Its opposite is stationary, meaning motionless.

To pertain means to be related to; to be relevant. Its opposite is to be irrelevant.

Pertinacity means determination; firmness; steadfastness. Its opposite is vacillation, meaning hesitation; indecision; uncertainty.

Petrous means very dense; rocklike. Its opposite is fluffy meaning feathery; very light.

Philistine means commonplace in ideas and tastes. Its opposite is connoisseur, meaning a critical judge of art and music.

Phlegmatic means apathetic; indifferent; calm. Its opposite is showing excitement.

Pied means spotted; freckled. Its opposite is solid-coloured.