butter wouldn't melt in one's mouth

Be overly coy or demure; be insincere. For example, She looked quite innocent, as though butter wouldn't melt in her mouth, but we knew better. Already a proverb in John Heywood's collection of 1546, this metaphoric expression alleges that one is literally so cool that butter inside the mouth would not melt.


Nearby words

  1. butter someone up,
  2. butter spreader,
  3. butter tart,
  4. butter tree,
  5. butter up,
  6. butter-and-egg man,
  7. butter-and-eggs,
  8. butter-fingered,
  9. butterball,
  10. butterbread

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.