Hindmost : furthest back, latest or ultramodern.
Disposed : inclined or willing.
Mature : fully developed physically, full-grown.
Premature : occurring or done before the usual or proper time, too early.
Unimportant : lacking in importance or significance.
Foremost : most prominent in rank, importance, or position.

So, antonym is Unimportant.
 

FAINT-HEARTED : A faint-hearted person might choose not to go on the steepest roller coaster or watch the scariest horror films. Faint-hearted was first used in the fifteenth century, and it combines the original meaning of faint, "lacking in courage," with hearted, or "at heart."
Stout-hearted : Stout describes a heavily built but usually strong and healthy body: a handsome stout lady. Fat, an informal word with unpleasant connotations, suggests an unbecoming fleshy stoutness; it may, however, apply also to a hearty fun-loving type of stout person: a fat old man; fat and jolly.

The antonym of PERENNIAL is Rare.

Honorary means doing something or serving without taking money or salary may be for own interests or for Honor.

LOQUACIOUS : talkative.
Reticent : not revealing one's thoughts or feelings readily.
Talkative : fond of or given to talking.
Garrulous : excessively talkative.
Verbose : using or expressed in more words than are needed.

Antonym of LOQUACIOUS is Reticent

The antonym of HAPLESS is Fortunate.

In this sentence we would be selecting the word which is opposite to "acquitted" from the given options.
Acquit means to decide that someone is not guilty of a crime. Thus, the opposite would be to blame someone or charge someone guilty of a crime.
If we look into the options:
Entrusted means to give someone the responsibility of doing something
Convicted means to prove someone guilty of a crime. It is the correct option.
Burdened means heavily laden or encumbered or someone who has been given a lot of lead. 
Freed means not held physically.
 

Opposite word of dutiful is remiss.

ZENITH : highest point.
Acme : zenith.
Top : the highest or uppermost point.
Nadir : the lowest or most unsuccessful point in a situation.
Pinnacle : the most successful point.

Antonym of ZENITH is Nadir.

Meticulous : showing great attention to detail; very careful and precise.
Slovenly : careless; excessively casual.
Meretricious : apparently attractive but having no real value.
Shaggy : (of hair or fur) long, thick, and unkempt.
Mutual : (of a feeling or action) experienced or done by each of two or more parties towards the other or others.

Antonym of Meticulous is Slovenly

The antonym of Transparent is Opaque.

Equanimity : calmness and composure, especially in a difficult situation.
Excitement : a feeling of great enthusiasm and eagerness.
Duplicity : deceitfulness.
Dubiousness : unsettled in opinion.
Resentment : bitter indignation at having been treated unfairly.

Antonym of Equanimity is Excitement
 

Provocation : action or speech that makes someone angry, especially deliberately.
Destruction : the action or process of causing so much damage to something that it no longer exists or cannot be repaired.
Peace : freedom from disturbance; tranquillity.
Pacification : an attempt to create or maintain peace.
Vocation : a strong feeling of suitability for a particular career or occupation.

Antonym of Provocation is Pacification.