IPA: //ʌnˈɪntrəstɪŋ//
KK: /ʌnˈɪntrəstɪŋ/
Not causing any interest or excitement; dull and boring.
The lecture was so uninteresting that many students fell asleep.
Uninteresting → It is formed from "un-" (meaning not) and "interesting" (from Latin "interesse", meaning to be between or to matter). The word "uninteresting" means not interesting or lacking in interest.
Think of 'not' ('un-') making something 'matter' less ('interesse') — that's why uninteresting means it doesn't capture your attention.