The word 'windbreaker' is a transparent compound formed within Modern English. It logically combines the noun 'wind', referring to moving air, with the agent noun derived from the verb 'break', here used in the sense of 'interrupting or lessening the force of'. The suffix '-er' indicates an object that performs this action. Thus, the term's literal meaning, 'a thing that breaks the wind', perfectly describes its function as a protective garment. This straightforward compounding follows a common Germanic pattern for creating functional object names, similar to 'can-opener' or 'lawnmower'.

Structure: wind (air in motion) + break (to stop or lessen) + er (agent suffix) - wind: From Old English wind, of Germanic origin; from an Indo-European root shared by Latin ventus. The core sense is 'air in motion'. - break: From Old English brecan, of Germanic origin; from an Indo-European root meaning 'to burst, break'. Here, it functions in the sense 'to stop, interrupt, or lessen the force of'. - er: An agent suffix from Old English -ere, of Germanic origin, used to form nouns denoting a person or thing that performs an action.