Depends on caliber & velocity of the bullet.
Answer is Kevlar.
Kevlar fabric
Bullet proof Vests
The cloth commonly used in bulletproof vests is typically made from a strong synthetic fiber called Kevlar. Kevlar is known for its high tensile strength and ability to absorb and disperse impact energy, making it an ideal material for ballistic protection. The fabric is woven into multiple layers to create a strong and flexible barrier against bullets and other projectiles. This design helps to slow down and deform the bullet, spreading its force over a larger area and reducing the likelihood of penetration.
The best-known bullet-proof material is probably Kevlar.
Bullet-proof vests are made of Kevlar as are motorcycle re-enforcement pads. Kevlar is extremely strong weave of synthetic fibre which has the added feature of being flexible.
Kevlar is a very dense polyamide. It has a high tensile strength, making it useful in several ways, such as bullet-proof vests.
It is used as a bullet-proof material and also, surprisingly, canoes.
It's a special kind of polymer, related to nylon, woven in certain patterns that enhance its ability to absorb and redirect the energy from a bullet. Note, that Kevlar (and all related materials) aren't really bullet "proof", rather they are bullet "resistant". They resist the passage of a bullet - for certain size and speed bullets, this resistance is enough to prevent it passing through the material, but for others, the bullet still retains enough energy to penetrate the material. Thus, all bullet resistant materials and designs are rated according to the type of bullet they are able to stop.
Kevlar is used to stop some bullets. Normally it will stop pistol rounds but other rounds , especially an anti tank round.
I don't understand what your asking but, kevlar body armor is an example of a layered fiber that catches the bullet while dissapating its energy, if that's what your asking.