easy [ME] Both easy and ease [ME] go back via Old French aisier ‘put at ease, facilitate’ to Latin adjacens ‘lying close by’, source also of adjacent [LME]. The Middle English words had senses such as ‘comfortable, convenient’ as well as ‘not difficult’. Easy-peasy, ‘childishly easy’, is only recorded from the 1950s. The ‘peasy’ is simply a rhyme and the childish word intensifies the sense.