PREFIX
(加在表示过程、品质、状态等的词前面)不，非，相反，缺乏
Dis- is added to some words that describe processes, qualities, or states, in order to form words describing the opposite processes, qualities, or states. For example, if you do not agree with someone, you disagree with them; if one thing is not similar to something else, it is dissimilar to it.