Meaning of blankety-blank

blank•e•ty-blank

Pronunciation: (blang'ki-tē-blangk'), [key]
— adj., adv. Informal.
  1. damned; darned (used to imply an omission of an unprintable or unspeakable word): The blankety-blank motor stalled again.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.