The word "吗啡" (mǎfēi) is formed through a purely phonetic borrowing process, where the two characters are chosen not for their meanings but solely for how their combined sounds approximate the English word "morphine". It is a direct transliteration, with "吗" (mǎ) capturing the initial "mor" sound and "啡" (fēi) representing the "phine" ending, resulting in a compound that functions as a single, unified loanword for the substance.