The word "ASSASSINATION" has 4S , 3A , 2I , 2N , T , O , 4S are together. this is considered as one block as 1 letter. we have 3A , 2I, 2N , 4S , T , O
Therefore , Number of words = Number of Permutations of 3A , 2I , 2N , 4S , T , O = 10! / 3!2!2!
= 10X9X8X7X6X5X4X3X2X1 / (3X2X1) X (2X1) X (2X1)
= 10X9X8X7X5X3X2 = 151200