Emily Dickinson Lexicon

ISH, n.

A termination of English words, is, in Sax. isc, Dan. isk, G. isch; and not improbably, it is the termination of esque, in French, as in grotesque, It. esco, in grotesco, and the Latin termination of the inceptive verb, as in fervesco. Annexed to English adjectives, ish denotes diminution, or a small degree of the quality; as, whitish, from white; yellowish from yellow. Ish annexed to names forms a possessive adjective; as, in Swedish, Danish, English. Ish annexed to common nouns forms an adjective denoting a participation of the qualities expressed by the noun; as, foolish, from fool; roguish, from rogue; brutish, from brute. This is the more common use of this termination.