"You canker blossom!" 3 Shakespearean Insults
1831, from French plantigrade "walking on the sole of the foot" (1795), from Latin planta "sole of the foot" (see plant (n.)) + gradus "step" (see grade (n.)).
plantigrade plan·ti·grade (plān'tĭ-grād')adj. Walking with the entire sole on the ground, as humans do.