'wheezer' originates from English, specifically from the verb 'wheeze' plus the agentive suffix '-er'; 'wheeze' is an imitative word representing a breath/sibilant sound.

'wheeze' appeared in Middle English (e.g. forms like 'wheesen' or similar imitative variants) and developed into the modern verb 'wheeze'; adding '-er' produced the agent noun 'wheezer'.

Initially, the root imitated the sound of labored or whistling breath; over time it came to mean both the action ('to wheeze') and, with '-er', a person or thing that wheezes; informally it also gained a secondary sense of something remarkable or especially difficult.