An uncommon modern English-style name likely formed for sound and style rather than a clear traditional etymology.
Knash is a modern invented name built on the phonetic skeleton of Nash — an Old English topographic name meaning "at the ash tree," derived from the Middle English phrase "atten ash" compressed over centuries into a single syllable. Nash has a distinguished surname history, most notably through John Nash (1752–1835), the British architect who redesigned much of Regency London, and John Forbes Nash Jr. (1928–2015), the mathematician whose struggle with schizophrenia and genius-level game theory work was immortalized in *A Beautiful Mind*.
The underlying name thus carries both architectural grandeur and intellectual intensity. The silent-K prefix transforms Nash into Knash, placing it in the small but evocative company of English words where K precedes N: knave, knight, knell, knack, knife — a remnant of Old English and Old Norse pronunciation where the K was once voiced. By grafting this silent letter onto Nash, the name acquires a visual weight and a faint medievalism that the bare form lacks.
It also creates a name that looks more complex than it sounds, an interesting inversion of the usual spelling-name relationship. There is an unavoidable sonic proximity to "gnash" (to grind teeth), which gives Knash a faint edge — a tiny growl embedded in its letters. For parents drawn to names with quiet intensity, this is a feature rather than a flaw. Knash sits in the current creative-naming tradition that values monosyllabic force, visual distinctiveness, and names that feel like they were excavated from an old manuscript rather than manufactured from whole cloth.