quaking

The word 'quaking' is built upon the core verb 'quake', which has ancient roots in the Proto-Germanic language, likely from a base meaning 'to shake' or 'to tremble'. This verb passed into Old English as 'cwacian', retaining its core sense of physical shaking. The addition of the '-ing' suffix, a productive grammatical element in English since its earliest stages, transforms the action into an adjective describing the state of shaking or a noun naming the action itself. Thus, the literal sense of the physical motion has extended metaphorically to describe emotional states like fear, maintaining a direct link from its ancient physical meaning to its modern abstract usage.

Structure: quak (shake) + ing (present participle suffix) 'quak' is from Middle English 'quaken', of Old English and Germanic origin, related to the verb 'quake'. '-ing' is a suffix from Old English '-ende', '-inge', used to form present participles and verbal nouns.