'rarely-updated' originates from the combination of 'rarely' and 'updated', where 'rarely' means 'not often' and 'updated' means 'made more modern or current'.

'rarely' and 'updated' were combined in modern English to form the compound adjective 'rarely-updated'.

Initially, 'rarely' meant 'not often', and 'updated' meant 'made more modern or current'. The combination retains these meanings to describe something that is not often made more modern or current.