grievous

the word 'grievous' originates from the middle english 'greven', a verb meaning to cause grief or harm. this verb itself is derived from the old french 'grever', which traces back to the latin adjective 'gravis', meaning heavy, serious, or severe. the latin 'gravis' is believed to come from the proto-indo-european root gʷreh₂-, meaning heavy. the suffix '-ous', from latin '-osus', denotes 'full of' or 'characterized by'. therefore, the literal construction 'full of grief' or 'characterized by seriousness' evolved into the modern abstract meaning of something being extremely severe, serious, or causing great sorrow.

Structure: griev (to cause grief) + ous (adjective-forming suffix) griev (from middle english 'greven', meaning to cause grief, ultimately from latin 'gravis', meaning heavy, serious); ous (a suffix forming adjectives, from latin '-osus', meaning full of, prone to)