'spine-chilling' originates from Modern English as a compound of 'spine' and the present participle 'chilling', where 'spine' ultimately comes from Latin 'spina' meaning 'thorn, backbone' and 'chill' comes from Old English roots meaning 'cold'.

'spine' changed from Old English 'spina' (itself ultimately from Latin 'spina') into Middle English 'spine' and modern English 'spine'; 'chill' evolved from Old English words for 'cold' (e.g. 'ċēald' / 'ceald') into Middle English 'chillen'/'chill' and the modern verb/adjective 'chill', and the compound 'spine-chilling' arose in Modern English to describe something that figuratively 'chills the spine'.

Initially, the components referred to a literal coldness affecting the spine ('to make the spine cold'); over time the compound came to be used figuratively to mean 'causing terror or an involuntary shiver' and more broadly 'very intense or affecting'.