This article considers the notion of ambiguity and its treatment by critics and theorists from a perspective informed by the work of Slavoj Žižek, according to which ambiguity should not be conceived as an exceptional ‘grimace’ of language’s deeper, more genuine ‘Unambiguity’; rather, the pervasive fantasy of Unambiguity should be thought of as the grimace of ambiguity – a convenient invention whose function is to mask the Void of a generalised indeterminacy feared by literary critics. It examines not only ambiguity’s ideological functions in literature, but ideology’s role in the critical conceptualisation of ambiguity. Eleanor Cook’s article, ‘Ambiguity and the Poets’, is taken to exemplify the much-maligned concept’s strangely persistent usefulness for an enriched understanding of poetry, but also the contradictoriness of the positions adopted by liberal interpreters. Revisiting poems by Elizabeth Bishop and Wallace Stevens discussed by Cook, and adding a reading of Tess Gallagher’s ‘Instructions to the Double’, the article demonstrates 1) the social character of ambiguity in those texts, and 2) how the moral hesitation about linguistic instability evident in the language of Cook’s article – ambiguity’s ‘mixed reputation’ – highlights anxieties around sexual and economic power within critical discourse. Critics’ implicit and ever-frustrated desire for ‘Unambiguity’ (an ideal of stable semantics and a correspondingly well-ordered society) is symptomatic of the contradictions of their historical moment and the bourgeois assumptions of ‘traditional’ literary criticism. It is therefore proposed, in conclusion, that unblinking attention to the unfinished, ambiguous nature of social and linguistic reality is a more effective path to political change, and indeed to the effective appreciation of poetry, than unspoken appeals to this fantasy of unachievable Unambiguity.