'razor-focused' originates from a modern English compound combining 'razor' and 'focused'. 'razor' originates from Old French 'rasour' (from Vulgar Latin *rasorium) where the root 'radere' meant 'to scrape'. 'focused' derives from Latin 'focus' meaning 'hearth, point', adopted into English scientific/figurative use and formed into the past-participial adjective 'focused'.

'razor' changed from Middle English 'rasor' (borrowed from Old French 'rasour') and eventually became 'razor' in modern English. 'focus' (Latin 'focus') was adopted into scientific English in the 17th–18th centuries; the adjectival form 'focused' developed later as the past participle of the verb 'focus'. These elements combined in colloquial/metaphorical compounds (e.g., 'razor-sharp', 'laser-focused') to form 'razor-focused'.

Initially 'razor' referred to the shaving tool and 'focused' to directing attention; over time the compound took on a figurative sense meaning 'as sharply concentrated as a razor', i.e., 'extremely narrow or precise concentration'.