This paper presents a usage-based cognitive approach to the different rates at which Icelandic masculine forms in nominative/accusative plural -ur are reanalysed as feminine. Of the 14.92% of nouns in plural -ur, 91.89% are feminine, others masculine. Syncretism in nominative/accusative plural is exceptionless among feminines, but relatively rare among masculines. Interestingly, plurals such as masculine eigendur ‘owners’, fætur ‘feet’, vetur ‘winters’ occasionally yield the feminine outputs definite eigendur-nar, fætur-nar, vetur-nar, and are sometimes modified by feminine forms of adjectives and determiners. As the full set of forms in plural -ur is highly schematic, we might expect reanalysis – viewed as a property of a schema’s productivity – to correlate proportionately with the frequency of corresponding masculine forms. However, corpus data for Icelandic betray a mismatch. Through a network model approach that emphasises prototype structure, minimal schematicity is shown to impact the rate of reanalysis by means of a gang effect.