IPA: /ˌʌnɪnˈtɛndɪd/
KK: /ʌnɪnˈtɛndɪd/
Not planned or meant; happening by accident.
The unintended consequences of the decision surprised everyone.
Unintended → It is formed from "un-" (meaning not) and "intend" (from Latin "intendere", meaning to stretch out or aim). The word "unintended" means not aimed at or not planned.
Think of something that is 'not' ('un-') 'aimed at' ('intend') — that's why unintended means something that happens without being planned.