about (आस पास) → exactly (अचूक)
abundance (बहुतायत) → lack (कमी)
advanced (विकसित) → elementary (प्राथमिक/ प्रारम्भिक)
ancestor (पूर्वज) → descendant (वंशज)
approximately (लगभग) → exactly (बिल्कुल)
certainly (निश्चित रूप से) → probably (शायद)
changeable (परिवर्तनशील) → constant (स्थिर)
complicated (जटिल) → simple (सरल)
compliment (तारीफ) → insult (अपमान)
compulsory (अनिवार्य) → voluntary (स्वैच्छिक)