[ blang-ki-tee-blangk ]
/ ˈblæŋ kɪ tiˈblæŋk /

adjective, adverb Informal.

damned; darned (used to imply an omission of an unprintable or unspeakable word): The blankety-blank motor stalled again.

Origin of blankety-blank

1885–90; after the practice of leaving blank spaces to represent profanity, as G-- d—- for God damn Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for blankety-blank