The word 'rarely-separated' is a compound adjective formed from 'rarely' and 'separated'. 'Rarely' originates from Middle English 'rarelī', meaning 'seldom', and 'separated' comes from Latin 'separatus', meaning 'to divide'.

'Rarely' evolved from Middle English 'rarelī', while 'separated' transformed from Latin 'separatus' through Old French 'separé'.

Initially, 'rarely' meant 'seldom', and 'separated' meant 'to divide'. Together, they describe something not often divided.