Arduous (Synonym)

• Steep
• Easy
• Trivial
• insignificant

Ponderous (Antonym)

• heavy
• bulky
• light
• laboured

Hideous (Antonym)

• frightful
• horrible
• beautiful
• ugly

He has been very feeble since his illness. (Synonym)

• Unwell
• Thin
• Weak
• Delicate

Some of their customs are barbarous. (Antonym)

• modern
• polite
• civilized
• none of these

Mr. Das is living a miserable life. (Antonym)

• boring
• painful
• unpleasant
• Happy

Every employee has liability to his office. (Antonym)

• consumption
• exemption
• presumption
• assumption

Reckless driving causes accidents. (Synonym)

• Rash
• Daring
• Courageous
• Bold

He used to involve with the confidential work of the University. (Synonym)

• Private
• Secret
• Trusted
• Hidden

Mr. Sen is a dynamic officer. (Synonym)

• forceful
• vigorous
• robust
• active