iffyEnglishOxford American Thesaurusiffy adjective informal 1 the windscreen's a bit iffy, but it's a good car: substandard, second-rate, low-grade, low-quality, of low quality, of poor quality; doubtful, dubious, questionable; informal not up to much; British, informal dodgy, ropy, not much cop; US, informal farkakte. ▷antonyms perfect. 2 that date is a bit iffy: tentative, undecided, unsettled, unsure, unreliable, unresolved, in doubt, in the balance; informal up in the air. ▷antonyms settled.