to the quick

1. To the exposed flesh, especially that which is tender. I've bitten my fingernails to the quick, and still, I can't stop myself!

2. To the deepest, most fragile part of oneself. Typically used to describe emotional wounds. I can't even look at her right now—that hurtful remark cut me right to the quick.

cut to the quick

To be deeply wounded; to have one’s feelings hurt. The noun “quick” means the living, as well as the most vital and important part; today it also means the very sensitive flesh between the fingernails and skin. To be touched to the quick, meaning to be deeply affected, has been used since the sixteenth century; it appears in John Heywood’s Proverbs and in several places in Shakespeare’s plays (Hamlet, The Comedy of Errors, and others). Another version is stung to the quick, as in “The last appellation stung her to the quick” (Henry Fielding, Joseph Andrews, 1742). “Cut to the quick” is a still later wording and has been a cliché since about 1850. See also quick and the dead.