one's head off

English

Adverb

Without restraint, hesitation, or inhibition; endlessly.
He has been worrying his head off all morning about how he will do on the finals.
- 1884, Mark Twain, chapter 37, in Adventures of Huckleberry Finn‎^[1], London: Thomas Nelson, page 327:
  [Tom] said now she couldn’t ever count them spoons twice alike again to save her life; and wouldn’t believe she’d counted them right, if she did! and said that after she’d about counted her head off, for the next three days, he judged she’d give it up and offer to kill anybody that wanted her to ever count them any more.
- 1998, Barbara Kingsolver, The Poisonwood Bible, New York: HarperFlamingo, p. 103,
  Late in the fall, the milky green bushes surrounding every house and path suddenly revealed themselves as poinsettias. They bloomed their heads off and Christmas rang out in the sticky heat […]

Usage notes

This expression is most often used with verbs expressing speech or other forms of vocalization, such as howl, laugh, sneeze, snore, squawk, talk, yawn, yell. An adjective may be used before the word head, for example: They were giggling their silly heads off. Other verbs that commonly occur with this expression are eat (also drink, smoke), lie (i.e. tell falsehoods) and work.