inadvertence

noun2

1. •
   The state or quality of being inadvertent; inadvertency; heedlessness; carelessness; negligence.

   • Many mistakes proceed from inadvertence.
2. •
   An effect or result of inattention; an oversight or mistake from negligence.

   • The size is an inadvertence like the tailor's stitches, to allow a style to emerge. — 1990