From Longman Dictionary of Contemporary Englishgrievousgriev‧ous /ˈɡriːvəs/ adjective formalSERIOUS SITUATION very serious and causing great pain or suffering a grievous shortage of hospital beds —grievously adverb He was grievously hurt by their betrayal.
Examples from the Corpus
grievous• In addition to the papal disregard of Canterbury's primatial claim over York, the monastic community suffered another grievous blow.• a grievous error• Congress now has a chance to correct its grievous error.• The Mormon Church considers abortion a grievous sin. 