vanity

noun5

1. •
   Excessive pride in or admiration of one's own abilities, appearance, achievements, or possessions.

   • It's not vanity, to me, it's my sanity — 1979
2. •
   A dressing table used to apply makeup, preen, and coif hair, in which the table is normally quite low and similar to a desk.

   • She was sitting in front of her vanity, brushing out her hair. — 2020
3. •
   A washbasin installed into a permanently fixed storage unit, used as an item of bathroom furniture.
4. •
   That which is vain, futile, or worthless; that which is of no value, use or profit.
5. •
   (no longer used) Any idea, theory or statement that is without foundation.

   • It is a vanity to say that if two stones are dropped from a tower, the heavier will experience the greater acceleration.