'rarely-built' originates from the combination of 'rarely,' meaning 'not often,' and 'built,' the past participle of 'build,' meaning 'to construct.'

'Rarely' comes from the Old French 'raer,' meaning 'seldom,' and 'built' from the Old English 'byldan,' meaning 'to construct.'

Initially, 'rarely' meant 'seldom' and 'built' meant 'constructed,' and this meaning has largely remained the same in modern usage.