IPA: /ˈsɔːŋˌraɪtər/
KK: /sɔŋˌraɪtər/
A person who creates the words or music for songs.
The songwriter wrote a beautiful melody that everyone loved.
Songwriter → It is formed from "song" (from Old English *sang*, meaning a musical composition) and "writer" (from Old English *writere*, meaning one who writes). A songwriter is someone who writes musical compositions or songs.
Think of a person who creates a 'musical composition' ('song') and is also 'writing' ('writer') it down — that's what a songwriter does.