lambaste [M17th] The early sense recorded for lambaste was ‘beat, thrash’: it comes from late 16th-century lam meaning ‘beat soundly’ and mid 16th-century baste meaning ‘thrash’, both probably of Scandinavian origin. The sense ‘criticize harshly’ dates from the late 19th century. The US expression on the lam ‘in flight’ developed from lam in the late 19th century.