'stonily' originates from Old English, specifically the word 'stānig' (from the root 'stān'), where 'stān' meant 'stone'; the adjective-forming element '-y' and the adverbial suffix '-ly' produced the modern adverb.

'stonily' changed from Middle English 'stony' (derived from Old English 'stānig'), the adjective 'stony' later took the adverbial suffix '-ly' to form the modern English adverb 'stonily'.

Initially it referred to being 'full of stones' or 'like stone' (physical sense), but over time it evolved into the figurative sense 'emotionally hard or cold', now meaning 'in a stony manner' (coldly, without feeling).