Meaning: The meaning of perilous is a dangerous situation, or something fraught with danger and risk.
Example: These highways are notoriously perilous.
Synonyms: Dangerous, Delicate, Precarious, Hazardous
Antonyms: Calm, Safe, Definite, Stable, Firm

Meaning: Insidious is something or someone who works in a subtle or sly way, or in an intent to trap.
Example: The insidious rumors destroyed the reputation of the company.
Synonyms: Sneaky, Tricky, Dangerous, Crooked
Antonyms: Fair, Honest, Sincere, Open

Meaning: To attain is to gain or accomplish something with effort
Example: I know that he lacked the ability to attain it.
Synonyms: Earn, Gain, Obtain, Grasp, Snag
Antonyms: Fail, Forfeit, Spend, Lose

Meaning: Tragic is something sad, harmful or fatal.
Example: It was a tragic love story.
Synonyms: Catastrophe, Appalling, Deadly, Dreadful
Antonyms: Blessed, Delightful, Fortunate, Harmless

Meaning: Contrary means opposite of something.
Example: This act of yours is contrary to our code of ethics.
Synonyms: Opposite, Conflicting, Hostile, Antagonistic
Antonyms: Agreeable, Consistent, Conforming, Obliging