| inhibition(control, check, limit, condition, restraint) |
| insubstantial(weak, poor, insufficient, scarce) |
| insufficiency(noun, weakness, lack, failing, flaw) |
| interference(noun, difficulty, obstacle, obstruction, impediment) |
| intervene |
| intervention(noun, difficulty, obstacle, obstruction, impediment) |
| jam-up(noun, difficulty, obstacle, obstruction, impediment) |
| joker(noun, difficulty, obstacle, obstruction, impediment) |
| knot(noun, difficulty, weakness, crack, fault) |
| lack(noun, weakness, crack, fault, failing) |
| limitation(noun, control, check, difficulty, limit) |
| limits(control, check, limit, condition, restraint) |
| lock(noun, control, check, difficulty, limit) |
| lousy(weak, poor, insufficient, scarce) |
| millstone(noun, difficulty, obstacle, obstruction, impediment) |
| mistake wrong(expression, slip, failure, fault, lapse) |
| monkey wrench(noun, expression, difficulty, obstacle, obstruction) |
| not enough(expression, adjective, weak, poor, insufficient) |
| obstacle(noun, difficulty, hindrance, problem, disadvantage) |
| obstruction(noun, delay, difficulty, hindrance, problem) |