English▸ adjective requiring considerable time and effort:
years of laborious training
the work is very slow and laborious.
▪ (of speech or writing style) showing obvious signs of effort and lacking in fluency:
she wrote in laborious, dictionary-assisted English.
– ORIGIN late Middle English (also in the sense ‘industrious, assiduous’): from Old French laborieux, from Latin laboriosus, from labor ‘labour’.