'rapidly-set-up' originates from the combination of 'rapidly' and 'set up', where 'rapidly' means 'quickly' and 'set up' means 'to establish or arrange'.

'Rapidly' and 'set up' were combined in modern English to describe something that is quickly established.

Initially, 'rapidly' meant 'quickly', and 'set up' meant 'to establish'. The combination retains the original meanings.