IPA: //ˌkaʊntərˈkʌltʃərəl//
KK: /ˈkaʊntərˌkʌltʃərəl/
Relating to a culture or movement that opposes or rejects the mainstream values and norms of society.
The band became famous for their countercultural messages that challenged societal expectations.
Countercultural → It is formed from "counter-" (meaning against) and "cultural" (from Latin "cultura", meaning cultivation or culture). The word describes a movement or lifestyle that is against the prevailing cultural norms.
Think of being 'against' ('counter-') the usual 'culture' — that's what countercultural means.