means To believe something is probably true or that someone is probably guilty, usually without full proof — or, as a noun, the person under that cloud of doubt.

from From Latin 'suspectus', the past participle of 'suspicere', meaning 'to look up at' or 'to look at from below' — built from 'sub-' (under) and 'specere' (to look). The image is of glancing up at someone sideways, that wary upward squint of distrust. It slipped into English through Old French in the medieval period, carrying that same uneasy gaze with it.