're-tinting' is formed from the prefix 're-' (from Latin 're-' meaning 'again') attached to 'tint'. 'Tint' comes from Old French 'teint'/'tinte', ultimately from Latin 'tingere' meaning 'to dye or color'.

'tint' developed from Old French 'tinte' (from Latin 'tingere' via Vulgar Latin) into Middle English forms such as 'tint' and later stabilized as modern English 'tint'. The prefix 're-' has been commonly used in Modern English to indicate repetition, producing 're-tint' and related forms like 're-tinting'.

Originally related broadly to 'dyeing' or 'coloring', the combined form 're-tinting' specifically denotes the action of applying a tint again or repeating a tinting process; the core idea of 'applying color' has remained but with an added sense of repetition.