| chief criterion(expression, reason, importance, fact) |
| fundamental premise(expression, reason, significance, fact) |
| key idea(expression, reason, significance, fact) |
| main criterion(expression, reason, importance, fact) |
| major asset(expression, reason, importance, fact) |
| primary reason(expression, reason, significance, fact) |
| top priority(expression, reason, importance, fact) |
| basic prerequisite(expression, reason, importance, fact) |
| dominant cause(expression, reason, significance, fact) |
| driving factor(expression, reason, significance, fact) |
| fundamental cause(expression, reason, significance, fact) |
| fundamental reason(expression, reason, significance, fact) |
| key reason(expression, reason, significance, fact) |
| main cause(expression, reason, significance, fact) |
| major cause(expression, reason, significance, fact) |
| major concern(expression, reason, significance, fact) |
| major reason(expression, reason, significance, fact) |
| primary cause(expression, reason, significance, fact) |
| basic cause(expression, reason, significance, fact) |
| center piece(expression, reason, factor, seriousness) |