In the SRD 5' Step is listed under the No Action in the Table: Actions in Combat. So he can not ready a 5' Step action but he can ready another action to do and still take his 5' step. So he could ready a standard attack on the condition the monster attacks me. Then he could take his 5' step (since this is a no action he can always do this if he has not moved any distance in the round).Benben said:No a 5' adjustment is a Miscellanous action or a Non-action depending on where in the SRD you're looking. You can take a 5' adjustment as part of a readied action as long as you've taken no other movement that round.
So in this case the player could ready to shout and then move back five foot back and it would be legal.