The word abate means to reduce in intensity or amount. Its antonym is enhance, which means to increase or improve.
Opposite words: Enhance, Intensify, Amplify, Augment, Strengthen.

The word deviant means departing from the norm or standards. Its antonym is regular, which means conforming to a standard or expected behavior.
Opposite words: Regular, Normal, Conventional, Standard, Typical.

The word acrid means having a strong, unpleasantly sharp smell or taste. Its antonym is sweet, which implies a pleasant and agreeable taste or smell.
Opposite words: Sweet, Pleasant, Mild, Fragrant, Aromatic.

The word startled means surprised or alarmed. Its antonym is relaxed, which implies calmness and lack of tension.
Opposite words: Relaxed, Calm, Composed, Unperturbed, Peaceful.

The word ostentatious means showy or pretentious. Its antonym is reserved, which means modest or unassuming.
Opposite words: Reserved, Modest, Humble, Unpretentious, Subtle.

The word morbid means an unhealthy or abnormal interest in disturbing subjects, or it can refer to a diseased state. Its antonym would therefore be healthy, as it represents the opposite state of wellness or soundness.

Opposite words: Healthy, Wholesome, Cheerful, Normal, Vigorous.

The word quiescent means inactive, at rest, or dormant. Its antonym would therefore be active, as it represents the opposite state of rest or inactivity.

Opposite words: Active, Vigorous, Agitated, Operated, Lively.

The word "hirsute" means hairy or shaggy. The antonym (opposite) of "hirsute" is bald, which means lacking hair.

Opposite words: Bald, Smooth, Glabrous, Bare, Shaven, Depilated.

"Parallelism" refers to things being aligned in a similar direction, often in a balanced or consistent way. The opposite of this would be "divergence," which refers to things moving or developing in different directions.

Opposite words: Disparity, Divergence, Incompatibility, Dichotomy, Polarity.

"Ruthless" means showing no mercy or compassion, being cruel or harsh. The opposite of this is "merciful," which means showing compassion or forgiveness, particularly when one has the power to punish or harm.

Opposite words: Merciful, Humane, Compassionate, Lenient, Affectionate.