Spank \Spank\ (sp[a^][ng]k), v. t. [imp. & p. p. {Spanked} (sp[a^][ng]kt); p. pr. & vb. n. {Spanking}.] [Of unknown origin; cf. LG. spakken, spenkern, to run and spring about quickly.] To strike, as the breech, with the open hand; to slap. [1913 Webster]