IPA: /ˌæntɪˈmɒnəˌpli/
KK: /ˌæntɪˈmɒnəˌpli/
Relating to laws or policies that oppose the establishment or maintenance of a monopoly.
The government implemented antimonopoly regulations to promote fair competition in the market.
Antimonopoly is formed from "anti-" (meaning against) and "monopoly" (from Greek "monopolion", where "mono-" means single and "polein" means to sell). The term refers to being against the control of a market by a single entity or seller.
Think of being 'against' ('anti-') a 'single seller' ('monopoly') — that's what antimonopoly means.