'narrow-fingered' is a compound formed from 'narrow' + 'finger' + the adjectival suffix '-ed'. 'narrow' originates from Old English 'nearwe' (also attested as 'narwe'), from Proto-Germanic *naru- meaning 'tight, close'. 'finger' originates from Old English 'finger', from Proto-Germanic *fingraz.

'narrow' changed from Old English 'nearwe' to Middle English 'narwe' and eventually became modern English 'narrow'; 'finger' has remained recognizably similar from Old English 'finger' to modern 'finger'. The compound form 'narrow-fingered' is a modern English adjectival formation using the past-participial/participial '-ed' to mean 'having' that quality.

Initially, the component words referred to 'tight/close' and the digit 'finger'; combined and with '-ed' the phrase has been used literally to mean 'having narrow fingers' and has retained that literal descriptive meaning in modern usage.