IPA: /ˌɒpəˈzɪʃənl/
KK: /ɑːpəˈzɪʃənl/
Relating to or showing disagreement or resistance to something.
The oppositional behavior of the students made it difficult for the teacher to maintain order in the classroom.
Oppositional → It is formed from "opponere" (meaning to place against) and the suffix "-al" (meaning relating to). The word "oppositional" describes something that is related to being against or in opposition to something else.
Think of something that is 'placed against' ('opponere') — that's why oppositional means relating to being against something.