度忘れ
どわすれ · dowasure · JLPT N1 · noun
memory
度 — 广 (shelter) + 庶 abbreviated (phonetic)
Originally depicted a hand measuring length under a shelter, meaning 'to measure' or 'a measure/standard.' From this came extended senses like 'degree,' 'extent,' and 'to pass through' (as in passing time). The reading 'dù' means degree/measure, while 'duó' preserves the older verbal sense of measuring.
忘 — 亡 (lose/perish) on top + 心 (heart) on bottom
忘 is a semantic-phonetic compound. The bottom 心 (heart/mind) gives the meaning, since forgetting happens in the mind, while the top 亡 (to lose, perish) supplies both the sound and the sense of something gone. Together they depict a thought lost from the heart — to forget.