IPA: /ˌʌn.kəˈmjuː.nɪ.kə.tɪv/
KK: /ʌnˌkɑːmjunɪˈkeɪtɪv/
Not willing to talk or share information with others.
He was uncommunicative during the meeting, giving only short answers.
Uncommunicative → It is formed from "un-" (meaning not) and "communicative" (from Latin "communicativus", meaning to share or make common). The word describes someone who is not inclined to share or communicate information.
Think of 'not' ('un-') being added to someone who is 'sharing' ('communicative') — that's why uncommunicative means not sharing or talking.