'Modern' is the antonym of 'ancient', referring to something contemporary.

'Natural' is the antonym of 'artificial', which refers to something made by human beings rather than occurring naturally.

'Rare' is the opposite of 'frequent', meaning not occurring often.

'Quiet' is the opposite of 'noisy'.

'Pessimistic' is the antonym of 'optimistic', which refers to a negative outlook.

'Fail' is the opposite of 'succeed'.

'Defeat' is the antonym of 'victory', indicating a loss in a competition.

'Scarce' is the opposite of 'abundant'.

'Reject' is the opposite of 'accept', meaning to refuse to take or agree to something.

'Modern' is the opposite of 'ancient'.

'Simple' is the opposite of 'complex', indicating something that is easy to understand or do.

'Late' is the opposite of 'early'.

'Contract' is the opposite of 'expand', meaning to decrease in size.

'Rare' is the opposite of 'frequent'.

'Sad' is the opposite of 'happy'.

'Diminish' is the opposite of 'increase', which means to make smaller or reduce.

'Quiet' is the opposite of 'noisy', referring to a lack of sound.

'Pessimistic' is the opposite of 'optimistic', indicating a tendency to see the worst aspect of things.

'Complicated' is the opposite of 'simple', meaning something that is difficult to understand.

'Fail' is the opposite of 'succeed', indicating a lack of success.

'Defeated' is the opposite of 'victorious'.

'Defeat' is the opposite of 'victory', indicating loss.

'Obscure' means not visible or hard to see, which is the opposite of 'visible'.

'Descend' means to go down, which is the opposite of 'ascend'.

'Simple' is the antonym of 'difficult', indicating ease.

'Contract' means to become smaller, which is the opposite of 'expand'.

'Rare' is the antonym of 'frequent', indicating something that does not happen often.

'Selfish' is the antonym of 'generous', indicating a lack of willingness to share.

'Heavy' is the opposite of 'light'.

'Quiet' is the antonym of 'noisy', meaning making little or no sound.