One Word Substitution

Option (1) is correct.

Option (3) is correct. Amnesty refers to general pardon for offenses, especially political offenses, against a government, often granted before any trial or conviction. 

Option (3) is correct. Antidote cures or counteracts effect of poison / or ill effects of another medicine.

Option (2) is correct.

Option (3) is correct. Avaricious means characterized by avarice; greedy; covetous. 

Option (3) is correct.

Option (4) is correct.

Correct answer is option 1.

Correct answer is option 4. Peer means equal and friends and mates are companions.

Fastidious means very attentive to and concerned about accuracy and detail, which manifests as being difficult to please or satisfy. The word comes from Latin 'fastidium' meaning loathing or disgust. Affable means friendly and approachable, obstinate means stubborn, and audacious means bold or daring.

Contemporary means living or happening in the same period of time.
 

Convalescent is used to refer to a person who is recovering after an illness or medical treatment.

Fatal literally means causing death or capable of causing death. The word derives from Latin 'fatum' (fate). Dead is a state of being no longer alive, critical means seriously ill or dangerous, and alarming means causing concern or fear - but only fatal specifically means deadly.

Option 2 means a cosmopolitan person; citizen of the world.
 

Germicide refers to a substance or preparation that kills germs or microorganisms. The suffix '-cide' means killing, as in homicide (killing a person) or pesticide (killing pests). Fratricide means killing one's brother, infanticide means killing infants, and pesticide kills pests generally, not specifically germs.

Immigrate specifically means to come to live permanently in a foreign country. The prefix 'im-' means 'into' and 'migrate' means to move from one place to another. Migrate is the general term for moving, hibernate means to remain inactive, and nationalize means to transfer ownership to the government.

Imperceptible means something so subtle or slight that it cannot be noticed or perceived by the senses or mind. The prefix 'im-' means 'not' and 'perceptible' means capable of being perceived. Improbable means unlikely, impregnable means unbreachable (usually fortifications), and intangible means abstract or unable to be touched.

Inaudible means incapable of being heard. The prefix 'in-' means 'not' and 'audible' comes from Latin 'audire' (to hear). Visible relates to sight, not sound. Audible is the opposite - capable of being heard, and invisible relates to sight, not hearing.

Correct answer is option 1. It means without preparation; offhand. (Ex means out of, Tempore means time, i.e. out of time; impromptu)

Incorrigible means incapable of being corrected, reformed, or improved - typically describing a person who persists in bad behavior. The prefix 'in-' means 'not' and 'corrigible' means able to be corrected. Incredible means unbelievable, incurable means untreatable (usually diseases), and indelible means unable to be erased.

Indelible means making marks that cannot be removed, erased, or washed away. The prefix 'in-' means 'not' and 'delible' comes from Latin 'delere' (to wipe out). Indefatigable means tireless, ineffable means too great to be described in words, and inexorable means unyielding or inevitable.

Inexplicable means unable to be explained or accounted for; puzzling. The prefix 'in-' means 'not' and 'explicable' means able to be explained. Ineligible means not qualified, infallible means incapable of error, and inexpressible means unable to be put into words.

Correct answer is option 3. It means tending to believe too readily; easily convinced.
 

Infallible means incapable of making mistakes or being wrong. The prefix 'in-' means 'not' and 'fallible' means liable to error. Incurable means untreatable, incorrigible means uncorrectable, and indelible means permanent or unable to be erased.

Inimitable means so distinctive or excellent as to be impossible to copy or imitate. The prefix 'in-' means 'not' and 'imitable' means capable of being imitated. Insatiable means impossible to satisfy, invincible means unconquerable, and irrevocable means unable to be reversed.