| deep(adjective, tough, severe, difficult, important) |
| far-reaching(adjective, tough, severe, important, significant) |
| fateful(adjective, tough, severe, important, significant) |
| fell(severe, weighty, aper, demoniac, crucial) |
| formidable(adjective, tough, severe, important, significant) |
| grave(adjective, tough, severe, deep, meaningful) |
| hard(adjective, tough, severe, important, significant) |
| laborious(adjective, tough, severe, important, significant) |
| meaning business(expression, adjective, tough, severe, important) |
| meaningful(adjective, tough, severe, important, significant) |
| no joke(expression, adjective, tough, severe, important) |
| no laughing matter(expression, adjective, idiom, tough, severe) |
| of consequence(expression, adjective, tough, severe, important) |
| operose(adjective, tough, severe, important, significant) |
| playing hard ball(expression, adjective, idiom, tough, severe) |
| serious(adjective, weighty, aper, demoniac, crucial) |
| smoking(adjective, tough, severe, important, significant) |
| sobering(adjective, tough, severe, important, significant) |
| strictly business(expression, adjective, tough, severe, important) |
| tough(adjective, severe, difficult, important, significant) |