forgetfulness
forgetful
+
-ness
https://gyazo.com/0a795a6ad40d427e08f2174ff1a4c8cd
source:
Meme tatane | Wiki | Anime Amino
noun
lapse
of
memory
:
物忘れ; 健忘症.
e.g.
she teased him for his forgetfulness.