'offset' originates from the combination of the prefix 'off-' and the verb 'set', where 'off-' meant 'away' and 'set' meant 'to put or place'.

'offset' changed from Middle English forms such as 'ofsetten'/'offseten' (formed from 'off' + 'set') and eventually became the modern English word 'offset'; the adverbial form 'offsettingly' is a later derivation built from the present-participle 'offsetting' + '-ly'.

Initially it meant 'to set off, put away, or start (something apart)', but over time it evolved into the sense 'to counterbalance or compensate', which underlies modern uses like 'offset' and derived forms such as 'offsettingly'.