| key factor |
| clincher |
| clinching factor(expression, importance, significant, valuable) |
| controlling influence(expression, importance, significant, valuable) |
| critical importance(expression, importance, significant, valuable) |
| crucial importance(expression, importance, significant, valuable) |
| crucial significance(expression, importance, significant, valuable) |
| decisive importance(expression, importance, significant, valuable) |
| fundamental importance(expression, importance, significant, valuable) |
| leading cause(expression, reason, importance, significance) |
| basic cause(expression, reason, importance, significance) |
| basic condition(expression, reason, importance, significance) |
| basic premise(expression, reason, importance, significance) |
| basic prerequisite(expression, reason, importance, significance) |
| basic term(expression, reason, importance, significance) |
| bottom line(expression, reason, importance, significance) |
| break point(expression, reason, importance, significance) |
| center piece(expression, reason, importance, significance) |
| central element(expression, reason, importance, significance) |
| chief criterion(expression, reason, importance, significance) |