'irregularly-sent' originates from the combination of 'irregularly' and 'sent', where 'irregularly' is derived from the Latin 'irregularis', meaning 'not regular', and 'sent' is the past participle of 'send', from Old English 'sendan'.

'irregularly' evolved from the Latin 'irregularis', and 'sent' from Old English 'sendan', eventually forming the modern English term 'irregularly-sent'.

Initially, 'irregularly' meant 'not regular', and 'sent' meant 'dispatched'. Together, they describe something dispatched in a non-regular manner.