Folk-etymological

In fact, it would seem that puerca is the folketymological form; […]

Zafarambol (Zafranbolu, Safranbolu). The name has not been explained properly (Ramsay, HG 324, from Θεοδωρίαν πόλιν is impossible; Wittek, Byz. 10 [1935] 40 note 4: from (εἰ)ς Άδριανούπολιν with folketymological transformation is not convincing); […]

In medical terminology, καταμήνια katamḗnia n.pl. 'menstruation' (derived from μήν mḗn 'month') was taken up by Oribasius latinus (6th c.) as cataminia with Middle Fr. catimini; the i of the latter reflected the folketymological influence of catir 'to hide', which also accounted for the semantic shift of the French idiom en catimini 'in secret'.

Their rejection, to a certain extent, of the role of nurturing mothers was symbolized by their searing of their right breasts, a practice justified by folk-etymological derivations of their name from a-privative and mazos, ‘breast’ (although the ostensible purpose of the searing was to facilitate bowmanship, and Amazons are often spoken of as rearing children).

As Georges Van Den Abbeele has noted, the OED offers two etymologies: “the more philologically valid formation of the word from com + munis (that is, with the sense of being bound, obligated, or indebted together) and the more folk-etymological combination of com + unus (or what is together as one)” (xi).

Those who deny the synchronic relevance of backformation would hold that backforming x from y is simply the folk-etymological assumption that x is the derivational source of y.

Whatever the further ramifications of such a Greek-Iranian term for ‘sieve’ (*pelwi- : plewi-, lost in common usage in Greek), it short-circuits customary Greek root-etymologies, not just such standbys as πολύς/πλείων ‘many’ or πλέος ‘full’ or Lat. pulvis ‘dust’ / Skt. palā́va-, Lith. pelai̇̃ ‘chaff’, but also folketymological connections with πλέω ‘sail’ (implicit in Hesiod, Erga 618-626, where the setting of the Pleiades in late October marks the end of the seafaring season) and πέλεια or πελειάς ‘dove’.

The name [Kuhl] has been altered by folketymological association with the High Ger. word kuhl cool (MHG küele).