'irregularly-built' originates from the combination of 'irregularly' and 'built', where 'irregularly' comes from Latin 'irregularis', meaning 'not regular', and 'built' is the past participle of 'build', from Old English 'byldan'.

'irregularly-built' changed from the Old English word 'byldan' to the modern English word 'built', combined with 'irregularly' to form the adjective.

Initially, 'irregularly' meant 'not regular', and 'built' meant 'constructed'. Together, they describe something constructed without a regular pattern.