Causing grief, pain, or anguish: a grievous loss. (adjective)
Serious or dire; grave: a grievous crime. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "grievous" in a sentence
"I use the word grievous to connote harms that are severe."
"And that, Steve-o, is what we call a grievous moral error."
"What makes them to the regenerate "not grievous," is faith which "overcometh the world" (1Jo 5: 4): in proportion as faith is strong, the grievousness of God's commandments to the rebellious flesh is overcome."