IPA: //ˌʌn.kənˈteɪ.nə.bəl//
KK: /ʌnˈkənˌteɪnəbl/
Describing something that cannot be held back or controlled.
The excitement in the room was uncontainable as the team celebrated their victory.
Uncontainable → It is formed from "un-" (meaning not), "contain" (from Latin "continere", meaning to hold together), and "-able" (meaning capable of). The word describes something that is not capable of being held together or restrained.
Think of something that cannot be 'held together' ('contain') and is 'not' ('un-') capable of being restrained.