In our experiment, the Saussurean postulate of arbitrariness has been empirically tested in order to see whether it can be applied to all words to the same extent. Three hundred participants were asked to match Czech words with their Hindi translations. One set of words was randomly chosen from a Hindi corpus (set A); the second set consisted of both randomly chosen words and words categorized as ideophones (set B). The participants were successful in matching both sets (the lower level of the confidence interval is about 7% above random guessing), and their performance showed unexpected patterns: For one, not only iconic properties (the sound qualities) but also iconic structures such as reduplication are an important distinctive features, and recipients are able to exploit this. Moreover, even words considered to be non-iconic (set A) apparently contain a degree of iconicity, which participants are able to draw upon. However, participants appear to lose this ability when non-iconic words are presented in the context of words with evidently abundant iconicity (set B). The effect resembles the accommodation process which is known for other senses; therefore, we call the effect “Iconicity flash blindness”.