Multiple choice

Directions: Fill in the blank with the correct word.

As ________ as nails.

  1. hard

  2. firm

  3. strong

  4. rigid

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The correct answer is 'hard' because 'hard as nails' is a common idiom describing someone tough, unfeeling, or something very durable. 'Strong' and 'rigid' are related but 'hard' is the established word in this expression.