Choose the most appropriate ANTONYM of the given word.

Strengthen

Weaken

The most appropriate antonym of the word strengthen is weaken.

• Strengthen means to make something stronger or more robust.
• Weaken means to make something weaker or less robust.

The other words do not have the same meaning as strengthen and are therefore not antonyms.

• Lengthen means to make something longer.
• Stiffen means to make something stiff or inflexible.
• Shaken means to make something unsteady or unstable.