'spasm-relieving' is a modern English compound formed from 'spasm' + the present participle 'relieving'. 'spasm' originates from Greek, specifically the word 'spasmos', where 'spasmos' meant 'a drawing or convulsion'; 'relieve' originates from Old French (from Latin), specifically the word 'relevare', where 're-' meant 'back/again' and 'levare' meant 'to raise or lighten'.

'spasm' entered English via Latin/medical usage from Greek 'spasmos'; 'relieve' came into Middle English from Old French (ultimately from Latin 'relevare'). The compound form 'spasm-relieving' is a recent English formation using these two elements to describe an agent or effect that reduces spasms.

Initially, 'spasm' referred specifically to a convulsive contraction and 'relieve' meant 'to lighten or ease'; over time the compound came to mean 'having the effect of easing or reducing muscle spasms' in medical and descriptive contexts.