| climax(noun, crisis, emergency, crunch, watershed) |
| crossroads(noun, climax, crisis, emergency, crunch) |
| decisive moment(noun, expression, climax, crisis, emergency) |
| defining moment(noun, expression, climax, crisis, emergency) |
| high noon(noun, expression, climax, crisis, emergency) |
| leading cause(expression, reason, importance, significance) |
| when push comes to shove(noun, expression, idiom, climax, crisis) |
| Rubicon(noun, climax, crisis, emergency, crunch) |
| 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) |
| center piece(expression, reason, importance, significance) |
| central element(expression, reason, importance, significance) |
| chief criterion(expression, reason, importance, significance) |
| chief reason(expression, reason, importance, significance) |
| controlling factor(expression, reason, importance, significance) |
| core driver(expression, reason, importance, significance) |
| critical factor(expression, reason, importance, significance) |