The alphabets in the given words are coded as follows :
 

M	I	S	T	A	K	E	N	D
9	7	6	5	4	1	2	8	3

I is coded as 7,
N as 8,
T as 5,
M as 9,
A as 4  and
E as 2.
So, the code for INTIMATE is 78579452.