IPA: //ʌnˌsɪstəˈmætɪk//
KK: /ʌnˌsɪstəˈmætɪk/
Not organized or done according to a plan or system.
The research was unsystematic, making it hard to draw clear conclusions.
Unsystmatic → It is formed from "un-" (meaning not) and "systematic" (from Greek "systematikos", meaning of or pertaining to a system). The word "unsystematic" means not organized according to a system or lacking a systematic approach.
Think of 'not' ('un-') being applied to something that is organized ('systematic'). This helps you remember that 'unsystematic' refers to something that is not organized or methodical.