'rarely-available' is a compound word formed from 'rarely' and 'available'. 'Rarely' originates from Middle English 'rar' meaning 'seldom', and 'available' comes from Old French 'avaler', meaning 'to be of use'.

'Rarely' evolved from the Middle English 'rar', while 'available' transformed from the Old French 'avaler' to the modern English 'available'.

Initially, 'rarely' meant 'seldom', and 'available' meant 'to be of use'. Together, they convey the idea of something not often obtainable.