invariability

n

1. unchangeability, unchangeableness, unchangingness, changelessness, immutability; firmness, fastness, fixedness, solidity, steadiness, stability; permanence, permanency, incorruptibility, irreversibility; constancy, reliability, dependability, regularity, certainty, indubitability; incontrovertibility, incontestability, irrefutability.

2. frequency, habitude, habitualness; persistence, re-lentlessness, endlessness, interminableness, inter-minability, ceaselessness; incessancy, monotony, routine; uniformity, sameness, regularity, symmetry, symmetricalness; smoothness, levelness, evenness