'smash-up' originates in English as a compound of the verb 'smash' and the particle 'up'. 'Smash' is of imitative (onomatopoeic) origin in English from the mid-16th century, meaning 'to break with a loud noise', and 'up' (from Old English 'up') intensifies or completes the action.

'Smash' appeared in Early Modern English (c.1500s–1600s) as an imitative verb meaning 'to break violently'. The particle 'up' has been used since Old English to indicate direction or completion. The compound 'smash-up' developed later in colloquial English (notably in 20th century) to refer specifically to collisions and wreckage.

Initially 'smash' meant simply 'to break violently' (often suggested by sound). Over time the compound 'smash-up' came to mean 'a violent collision' (especially vehicle crashes) and figuratively 'a disastrous failure' or 'a ruin'.