'rebating-friendly' is a modern English compound formed from the gerund 'rebating' (from the verb 'rebate') and the adjective 'friendly'. 'rebate' in English ultimately comes from Old French/Medieval Latin sources for terms meaning 'to beat down' or 'take back' and later developed the sense of a returned payment; 'friendly' comes from Old English 'freond' (friend) with the adjectival suffix '-ly'.

'rebate' entered English via Old French/Anglo-Norman and Middle English developments and came to mean a reduction or returned payment; 'friendly' derives from Old English words for 'friend' and an adjectival suffix. The compound 'rebating-friendly' is a recent, transparent formation in Modern English (20th–21st century) combining these elements to describe an attitude or policy toward rebates.

Initially, the components meant a returned payment ('rebate') and 'like/related to a friend' ('friendly'); combined in modern usage they mean 'favorable to rebates' rather than any literal social friendliness.