Choose the correct meaning of idiom: Tooth and nail

Correct — A. To fight tooth and nail is to fight with everything you have, very fiercely, holding nothing back.

The picture is literal: biting with the teeth and scratching with the nails, using every weapon the body has. The idiom keeps that sense of all-out effort → option (a), 'With full force or vigour'.

Why the others are wrong

• (b)
  Without planning — Without planning describes improvising, the sense of the idiom off the cuff. Tooth and nail says nothing about preparation; it measures how hard you fight.
• (c)
  Secretly and quietly — Secretly and quietly reverses the picture. Fighting with teeth and nails is open and violent, not hidden; secrecy belongs to idioms like on the sly.
• (d)
  Half-heartedly — Half-heartedly means without enthusiasm or full effort. That is the opposite of fighting tooth and nail, so it inverts the idiom rather than defining it.

This idiom is a picture, and the picture carries the meaning. Biting and scratching means using every weapon the body has, so the phrase stands for maximum effort in a struggle.

The options sort along one question: how hard, and how openly? Full force is maximum and open. Half-heartedly is minimum. Secretly is hidden.

Without planning is a different axis altogether: preparation, not effort.

Key facts

• Tooth and nail means with every available means, very fiercely.
• It is used after verbs of struggle, as in fight tooth and nail.
• Half-heartedly means without enthusiasm or full effort.
• Off the cuff means without preparation.

Common traps

• Mixing it up with by the skin of one's teeth, which means by a very narrow margin
• Reading the phrase as a picture of injury rather than of fighting

No directly related past PYQ was found.