Disinterested. This a typical tricky word for native speakers of English, because it is easily mixed up with "uninterested". Someone who is uninterested in something simply does not want to know anything about it (nemá zaujem), but someone who is disinterested has nothing to gain personally from the situation (nie je zaujatý), so they are not biased /bájast/ or prejudiced /predžedist/ either for or against one side or the other.

Parts of words like un- and dis- are called prefixes, and they have their own meanings. "Un-" means simply "not", so for example "unused" means new, never used. "Dis-" means something missing, lacking or removed, so "disused" means it was used in the past, but not any more, like a disused railway line. Other examples are "mis-", which means "in the wrong way", not as it was intended, so you might think that people sometimes "misuse" their cell-phones; and "ab-" means "in a very bad, deviant way", such as to abuse alcohol or drugs.