GRYPOSIS

grə̇ˈpōsə̇s, grīˈ- noun

( plural grypo·ses -ōˌsēz)

Etymology: Late Latin, from Late Greek grypōsis, from Greek grypousthai to become hooked (from grypos hooked, curved) + -sis — more at griffin

: abnormal curvature especially of the fingernail