'irregular-metered' is a modern English compound formed from 'irregular' + 'metered'. 'Irregular' originates from Latin, specifically the word 'irregularis', where the prefix 'in-' meant 'not' and 'regularis' related to 'rule'. 'Metered' ultimately comes from Greek 'metron' meaning 'measure', via Latin 'metrum' and later English 'meter/ metre'.

'metered' evolved from Greek 'metron' -> Latin 'metrum' -> Old French/Latin-influenced forms and Middle English 'metre/meter' and eventually the adjectival/past-participial form 'metered' in modern English. 'Irregular' derived from Latin 'irregularis' entered English via Old French and Medieval Latin forms, keeping the sense 'not regular', and the compound 'irregular-metered' is a straightforward modern English formation combining the two elements.

Initially, the parts meant 'not regular' (irregular) and 'measured' (metered). Over time the compound came to mean specifically 'having an uneven or nonstandard metrical pattern', a sense consistent with its components but specialized for poetic, musical, or rhythmic description.