One Word Substitution

Plagiarist refers to a writer who steals or uses another person's work as their own. Atheist is someone who doesn't believe in gods, while Anarchist opposes authority or government.

Indefatigable means tireless or incapable of being tired, which directly matches the meaning. Smart and Weak describe intelligence or strength, not endurance.

Biography is the written account of another person's life. Reminiscences are personal memories, while Tale is a fictional story.

Blonde refers to a person (usually woman) with fair complexion and light hair. Ugly means unattractive, while Dubious means doubtful or uncertain.

Accelerate means to increase speed or move faster. Creep and Sneak suggest slow, cautious movement.

Regicide specifically means the killing of a king (rex=king in Latin). Homicide is general murder, Matricide is killing one's mother, and Patricide is killing one's father.

Cosmopolitan refers to someone who is at home anywhere in the world, free from national limitations or prejudices. Native and Alien suggest belonging or not belonging to one specific place.

Improbable means unlikely to happen or not probable. Evident and Clear both suggest certainty or visibility, which are opposite concepts.

Aristocracy refers to a form of government where power is held by a small, privileged minority, usually the most wealthy or educated members of society (the nobility). Monarchy is rule by a single person (king/queen), while autocracy is rule by one person with absolute power.

A sinecure is a position or office that provides income but requires little or no work. Insolvent means unable to pay debts, while panacea is a solution for all problems.

An epitaph is a brief text honoring a deceased person, typically inscribed on their tomb or gravestone. Perpetuation means making something last indefinitely, while draft and sketch are preliminary versions of documents or drawings.

Posthumous means occurring after death. A posthumous child is born after their father's death. Pessimist describes someone with negative outlooks, optimist is the opposite, and illiterate means unable to read or write.

Omnipotent means having unlimited or complete power. Omnipresent means present everywhere simultaneously, which is different from all-powerful. Omni is just a prefix meaning 'all'.

Illegible means not readable or impossible to read due to poor handwriting or printing. Invincible means incapable of being conquered, while clear is the opposite of illegible.

Case of passive voice. The sentence is perfectly correct.