Identify the word that cannot be formed using the letters from the word 'YESTERDAY'.

Let's look at the letters present in the word 'YESTERDAY':
Letters: Y, E, S, T, E, R, D, A, Y (E appears twice, Y appears twice, others appear once).

Now evaluate the options:

* ERASE: E, R, A, S, E (All letters are present with correct frequency).
* STEADY: S, T, E, A, D, Y (All letters are present).
* SPORT: Contains the letters P and O, which are completely absent in 'YESTERDAY'. Therefore, 'SPORT' cannot be formed.
* DEAR: D, E, A, R (All letters are present).

Thus, 'SPORT' is the correct answer.