'sporadically-visible' originates from the combination of 'sporadic' and 'visible'. 'Sporadic' comes from the Medieval Latin 'sporadicus', meaning 'scattered', and 'visible' from the Latin 'visibilis', meaning 'able to be seen'.

'Sporadicus' transformed into the English word 'sporadic', and 'visibilis' became 'visible' in English, eventually forming the compound adjective 'sporadically-visible'.

Initially, 'sporadic' meant 'scattered or isolated', and 'visible' meant 'able to be seen'. The compound 'sporadically-visible' retains these meanings, indicating something that is seen at irregular intervals.