Antonyms

Mountain means An elevation of land higher than a hill.
Valley means An area of lowland between hills or mountains.

So, we can say that Mountain is an antonym for the valley.

Flagitious : Criminal.
Innocent : Not guilty of a crime or offence.
Vapid : Offering nothing that is stimulating or challenging.
Ignorant : Lacking knowledge or awareness in general.
Frivolous : Not having any serious purpose or value.

Antonym of Flagitious is Innocent.

Hollow means empty from inside or unfilled while Solid means a body covered from all sides.

Violent: using or involving physical force intended to hurt, damage, or kill someone or something.
Tame: (of an animal) not dangerous or frightened of people; domesticated.
Humble: having or showing a modest or low estimate of one's importance.
Gentle: having or showing a mild, kind, or tender temperament or character.
Harmless: not able or likely to cause harm.

Antonym of Violent is Gentle.

Relinquish : Voluntarily cease to keep or claim.
Abdicate : Renounce one’s throne.
Renounce : Formally declare one’s abandonment.
Possess : Have as belonging to one.
Deny : State that one refuses to admit the truth or existence of.

Antonym of Relinquish is Possess.

Quiescent : In a state or period of inactivity or dormancy.
Active : Ngaging or ready to engage in physically  energetic pursuits.
Dormant : Having normal physical functions suspended or slowed down for a period of time.
Weak : Lacking the power to perform physically demanding tasks.
Unconcerned : Showing a lack of worry or interest.

Antonym of Quiescent is Active.

‘Culpable', means guilty or blameworthy.
‘blameless’ which means innocent.

There is no meaning of miscomfort.
Discomfort is noun and uncomfortable is adjective its answer is discomfort.