| unchangeable(adjective, certain, limited, definite, inflexible) |
| undeniable(clear, simple, plain, obvious, valid) |
| undeviating(adjective, certain, limited, definite, inflexible) |
| undoubted(adjective, clear, sound, firm, plain) |
| undoubtful(adjective, strong, easy, firm, solid) |
| unequivocal |
| unfaltering(adjective, certain, limited, definite, inflexible) |
| unflinching(adjective, certain, limited, definite, inflexible) |
| unmistakable |
| unmodifiable(adjective, certain, limited, definite, inflexible) |
| unmovable(adjective, certain, limited, definite, inflexible) |
| unpreventable(expected, predictable, necessary, inexorable, undeniable) |
| unqualified(adjective, certain, limited, definite, inflexible) |
| unquestionable(adjective, clear, sound, plain, solid) |
| unwavering(adjective, certain, limited, definite, fixed) |
| warranted |
| well-founded(adjective, strong, easy, solid, certain) |
| without recourse(expression, expected, predictable, necessary, inexorable) |
| assertive(certain, sure, guaranteed) |
| audacious(certain, sure, guaranteed) |