嗅闻 is a literary, somewhat redundant compound verb meaning 'to sniff and smell' — essentially emphasizing the act of using the nose to detect scents. Both characters 嗅 (xiù) and 闻 (wén) individually mean 'to smell', so combining them intensifies or stylizes the action, often for poetic, descriptive, or formal effect. It’s rarely used in casual speech; instead, it appears in written descriptions — especially in nature writing, animal behavior accounts, or literary narratives where sensory detail matters.

This word frequently appears when depicting animals investigating their environment — such as dogs tracking scents or cats exploring new objects — or when portraying human characters engaging in deliberate, attentive smelling (e.g., evaluating wine or detecting danger). Its redundancy isn’t considered awkward in literary Chinese; rather, it adds rhythmic weight and vividness, much like English phrases such as 'look and gaze' or 'search and seek'.