expression, godan verb (-ku)
to lack the finishing touch; to be incomplete despite near perfection
Idiomatic expression derived from the Chinese story of a painter who added pupils to a dragon painting and brought it to life. Used when something is almost perfect but misses a crucial final detail.
See also: 画竜点睛 (がりょうてんせい)
His plan is well thought out, but the fundraising outlook is weak, so it lacks the finishing touch.
このケーキは味は完璧だが、飾り付けが地味で画竜点睛を欠いている。
This cake tastes perfect, but the decoration is plain, so it's missing that final touch.