IPA: /ˌʌn.kənˈvɛn.ʃən.əl/
KK: /ʌnˈkɒnvənʃənl/
Not following the usual rules or traditions; different from what is generally accepted.
Her unconventional ideas often lead to innovative solutions.
Unconventional → It is formed from "un-" (meaning not) and "conventional" (from Latin "conventionem", meaning agreement or assembly). The word "unconventional" means not adhering to established customs or norms, indicating a departure from what is generally accepted.
Think of 'not' ('un-') following the 'agreement' ('conventional') — that's why unconventional means not following the usual agreements or norms.