(n.) The quality or condition of being two or twofold; dual character or usage.

Janus ambivalence amphibologism amphibology amphiboly antinomy asymmetry biformity bifurcation cavil conjugation counterword dichotomy disproportion disproportionateness dodge double entendre double meaning double-talk doubleness doublethink doubling dualism duality duplexity duplication duplicity equivocacy equivocal equivocality equivocalness equivocation equivoque evasion haggling hair-splitting halving hedge heresy heterodoxy heterogeneity impenetrability imprecision inapprehensibility inarticulateness incognizability incoherence incommensurability incompatibility incomprehensibility inconclusiveness incongruity inconsistency inconsonance indefiniteness indistinctness inscrutability irony irreconcilability nonconformability nonconformity numinousness obscurity oxymoron pairing paradox polarity polysemant polysemousness portmanteau word pun quibbling ramblingness self-contradiction shift squinting construction subterfuge tergiversation twinning two-facedness twoness uncertainty unconformability unconformity unconnectedness unfathomableness unintelligibility unknowability unorthodoxy unsearchableness vagueness weasel word