だめ has a variety of meanings from merely “no!” and “don’t!” to “that’s not allowed” or “that’s not the right way to do it”. i’m no expert on how to write it though it seems to me that more frequently you would see だめ or even ダメ (for more emphasis). the kanji, for me, seem to weaken the force of it—and my guess is that using kanji for だめ would give a literary feel.
– A.EllettSep 24 '20 at 23:47