irregular.

(a loanword from Spanish)

Headword: 
irregular.
Principal English Translation: 

irregular
(a loanword from Spanish)

Orthographic Variants: 
irrecular, yrrecular
Attestations from sources in Spanish: 

tono irreculare = tono irregular
yzcatlqui tono yrrecular = He aqui el tono irregular (seventeenth-century Guatemala)
Fernando Horcasitas y Alfred Lemmon, "El Tratado de Santa Eulalia: un manuscrito musical náhuatl," Tlalocan 12 (1997), 102–103.