c. 1300, dalien, "to speak seriously, commune;" late 14c., "to talk intimately, converse politely," possibly from Anglo-French dalier "to amuse oneself," Old French dalier, dailer, which is of uncertain origin. Sense of "waste time" in any manner emerged by late 14c.; that of "to play, sport, frolic; flirt, engage in amorous exchanges" is from mid-15c. Meaning "to linger, loiter, delay (intransitive)" is from 1530s. Related: Dallied; dallying.