Etymology
A corruption of agnail (literally “painful (anguished) nail”), by folk-etymological reanalysis as hang + nail; from Middle English agnail, from Old English angnæġl, from ang- (“tight/painful”) + næġl (“nail”). The first part is from Proto-Germanic *anguz, from Proto-Indo-European *h₂énǵʰus (“narrow, tight”), while the second is from Proto-Germanic *naglaz, from Proto-Indo-European *h₃negʰ-. The first component, ang- is also the origin of anguish, anger, and angst, while næġl is the origin of nail. Compare more "pure" Scots angernail, and similarly folk-influenced dialectal variants wrangnail and ragnail, all meaning "hangnail" and from Middle English. Cognate with Old High German ungnagel and Old Frisian angneil, o(n)gneil.
Original sense of “loose strip of tissue”; the sense of “pointed c