the.com/sneak

means To move, act, or do something in a quiet, covert way so as to avoid being noticed.

from Sneak likely traces back to an Old English root, 'snican,' meaning to creep or crawl — the same ancient family that gave us 'snake.' The word sat quietly in dialect use for centuries before slithering into mainstream English, and it picked up its sense of 'cowardly tattletale' (the schoolyard 'sneak') only later, as the physical creeping became a metaphor for the moral kind.