Dutch uses prefixes to modify meaning. The prefix on- (similar to English un-) negates adjectives and some nouns: mogelijk (possible) → onmogelijk (impossible), gelukkig (happy/lucky) → ongelukkig (unhappy/unfortunate), bekend (known/familiar) → onbekend (unknown). This prefix is extremely productive — you can negate most adjectives this way.
The prefix mis- indicates something done wrongly: begrijpen (to understand) → misbegrijpen (to misunderstand), leiden (to lead) → misleiden (to mislead), bruiken? No: misbruiken (to misuse, from gebruik). The prefix ont- indicates removal or beginning: blokkeren (to block) → ontblokkeren (to unblock), dekken (to cover) → ontdekken (to discover), vangen (to catch) → ontvangen (to receive/welcome).
The prefix her- means doing again: denken (to think) → herdenken (to commemorate/re-think), gebruiken (to use) → hergebruiken (to reuse), schrijven (to write) → herschrijven (to rewrite), kennen (to know) → herkennen (to recognise). The prefix ver- creates verbs from nouns/adjectives or changes meaning: groot (big) → vergroten (to enlarge), betalen (to pay) → verbeteren (to improve). Prefix knowledge multiplies your effective vocabulary rapidly.