'honest-looking' originates from Modern English as a compound of 'honest' and 'looking'. 'Honest' ultimately comes from Latin 'honestus', meaning 'honorable' or 'respected', and 'looking' derives from the verb 'look' (Old English lōcian/locian) meaning 'to direct one's eyes' or 'appear'.

'honest' entered English via Old French and Latin ('honestus') and has meant 'honorable' or 'virtuous' since Middle English. 'Look' comes from Old English 'lōcian/locian' and developed into the Middle and Modern English verb 'look'. The compound 'honest-looking' arose in Modern English by combining the adjective 'honest' with the present participle 'looking' to form an adjectival phrase meaning 'appearing honest'.

Initially, 'honest' meant 'honorable' (and 'look' meant 'to direct one's eyes' or 'appear'); over time, combining them produced the newer, descriptive sense 'appearing honest' rather than asserting actual honesty.