RIDDLE

CAN ANY ONE CAN SOLVE THIS.............?????

I AM AN EIGHT LETTER WORD

I AM KEPT SECRET BY EVERYONE

MY 2,3,4 LETTERS IS AN ANIMAL

MY 3,5,6,7,8 LETTERS IS A FIGHTING WEAPON

MY 1,2 8 IS USED FOR WRITING EXAM

MY 3,4 LETTERS ARE SAME

FIND PLEASE