1. What does it mean?
입덕부정기 combines becoming a fan with a period of denial. It describes someone repeatedly watching or discussing an artist while insisting that they are merely curious and have not actually joined the fandom.
Also written or said as ipdeokbujeonggi
2. The nuance
It is a playful description, not a psychological diagnosis or a stage every fan must experience. Let people describe their own interests instead of pressuring them into a label.
3. Examples
“입덕부정기라더니 영상은 다 봤네.”
You say you're not a fan yet, but you've watched every video.
“나는 입덕부정기 없이 바로 팬이라고 인정했어.”
I skipped the denial phase and admitted right away that I was a fan.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.