'irregularly-offered' originates from the combination of 'irregularly' and 'offered'. 'Irregularly' comes from the Latin 'irregularis', meaning 'not regular', and 'offered' is derived from the Old English 'offrian', meaning 'to present or give'.

'Irregularly' changed from the Latin 'irregularis' to the Middle English 'irreguler', and eventually became the modern English 'irregularly'. 'Offered' evolved from the Old English 'offrian' to the Middle English 'offren', and eventually became the modern English 'offered'.

Initially, 'irregularly' meant 'not following a regular pattern', and 'offered' meant 'to present or give'. The combined term 'irregularly-offered' retains the essence of these meanings, indicating something not consistently available.