IPA: //ʌnˌsɛnseɪˈʃənl//
KK: /ʌnˌsɛnseɪˈʃənl/
Not exciting or dramatic; lacking in sensational qualities.
The film was quite unsensational, focusing more on character development than on action.
Unsensational → It is formed from "un-" (meaning not) and "sensational" (from Latin "sensatio" meaning feeling or perception, combined with the suffix "-al" meaning pertaining to). The word "unsensational" means not pertaining to or characterized by sensationalism or excitement.
Think of 'not' ('un-') being added to 'pertaining to feeling or excitement' ('sensational') — that's why unsensational means lacking excitement.