'reelingly' originates from English, specifically the verb 'reel', where the suffix '-ing' meant 'action or process' and the suffix '-ly' meant 'in the manner of'.

'reel' changed from older Old English forms such as 'hreol' or related verbs and eventually became the modern English verb 'reel'; the adjective/participle 'reeling' and the adverbial suffix '-ly' produced 'reelingly'.

Initially, 'reel' primarily meant 'to whirl or turn'; over time it extended to mean 'to stagger or feel dizzy', and the adverbial form came to mean 'in a dizzy or overwhelmed manner'.