IPA: //ˌʌltrəˈmɒdərn//
KK: /ˌʌltrəˈmɒdərn/
Extremely modern in ideas or style; completely up-to-date.
The building features an ultramodern design that attracts many visitors.
Ultramodern is formed from "ultra-" (meaning beyond) and "modern" (from Latin "modernus", meaning of the present time or recent). The word describes something that is beyond what is currently considered modern, representing the latest advancements or trends.
Think of 'beyond' ('ultra-') what is 'current' or 'recent' ('modern') to remember that 'ultramodern' refers to something that is extremely advanced or cutting-edge.
No commonly confused words.