IPA: //ʌn.kənˈstrʌk.tɪv//
KK: /ʌnˈkənstrʌktɪv/
Not helpful or useful; not contributing positively to a situation or discussion.
His unconstructive criticism did not help the team improve their project.
Unconstructive → It is formed from "un-" (meaning not) and "construct" (from Latin "construere", meaning to build). The word "unconstructive" means not building or contributing positively to a situation.
Think of 'not' ('un-') contributing to 'building' ('construct') — that's why unconstructive means not helping to build something positive.