A serious mistake that could cost someone his life is an example of a mistake that would be described as grievous.
- causing grief
- showing or characterized by grief: a grievous cry
- causing suffering; hard to bear; severe: grievous pain
- very serious; deplorable: a grievous fault
- atrocious; heinous: a grievous crime
Origin of grievousMiddle English grevous from Old French from grever: see grieve
- Causing grief, pain, or anguish: a grievous loss.
- Serious or dire; grave: a grievous crime.
Origin of grievousAnglo-Norman grevous from grever to harm, aggrieve from Latin gravāre to burden ; see grieve .
Usage Note: The pronunciation of grievous with three syllables as (grē′vē-əs), written as though there were an extra i in the spelling of the word, is commonly heard but is roundly criticized as a mispronunciation. Ninety percent of the Usage Panel in 2005 found the three-syllable pronunciation to be unacceptable.
(comparative more grievous, superlative most grievous)