Letter Quest: Grimm's Journey Remastered

There are two ways to get this achievement:

1. Wait until an enemy turns some of your tiles into cracked or plague tiles. Cracked tiles and plague tiles do no damage, so if you can spell a word with all cracked/plague tiles it will do zero damage
2. Wait until you face an enemy with a special requirement such as "only takes damage from 4-letter words," which is the case for the crystal star on stage 1. Spell a word of any length other than 4 letters and it will do zero damage.