The compound adjective 'suspicious-looking' is a relatively modern English formation that combines two elements, both with deep roots in the act of seeing. The first part, 'suspicious', originates from the Latin verb suspicere, meaning "to look up at" or "to mistrust," which itself is formed from sub- ("from below") and specere ("to look"). This etymology carries the sense of looking at someone from a position of doubt or wariness. The second part, 'looking', derives from the Old English verb lōcian, meaning to see or gaze. When combined, the word creates a logical and transparent meaning: something that has the appearance (looking) which arouses mistrust or doubt (suspicious). This evolution from separate verbs of perception to a unified descriptive term exemplifies how English builds precise meaning through compounding.

Structure: suspicious (adjective) + looking (present participle) - suspicious: From Latin suspiciosus, from suspicere (to look up at, mistrust). The root 'spic' relates to seeing or looking. In this compound, it functions as the core descriptive element. - looking: From Old English lōcian (to see, gaze). In this compound, it functions as a present participle, indicating the act or state of appearing.