tidy: [13] Tidy originally meant ‘timely, seasonable’ (it was a derivative of tide, in the now superannuated sense ‘time, season’). It early on evolved metaphorically to ‘goodlooking’, and hence ‘good’, but the modern sense ‘neat’ did not emerge until the 18th century. Titivate [19] may have been based on tidy. => tide, titivate[tidy etymology, tidy origin, 英语词源]