NIVARANA

These are mental obstacles, which stop us from reaching Samadhi (concentration and serenity).

Text from the Angutara Nikaya (Book V – Sutta 193)  

 

Kamacchanda : Sensual Desires "Suppose, Brahmin, there is a bowl of water mixed with red, yellow, blue, or crimson dye. If a man with good sight were to examine his own facial reflection in it, he would neither know nor see it as it really is. So too, Brahmin, when one dwells with a mind obsessed by sensual lust.”

Vyapada : Ill-Will 
"Suppose, brahmin, there is a bowl of water being heated over a fire, bubbling and boiling. If a man with good sight were to examine his own facial reflection in it, he would neither know nor see it as it really is. So too, Brahmin, when one dwells with a mind obsessed by ill-will, even those texts that have been recited over a long period do not recur to the mind, let alone those that have not been recited.”
Thina-middha : Sloth and Torpor “Suppose, Brahmin, there is a bowl of water covered over with water plants and algae. If a man with good sight were to examine his own facial reflection in it, he would neither know nor see it as it really is. So too, Brahmin, when one dwells with a mind obsessed by sloth and drowsiness. ”
Uddhaccha- kukkuccha : Restlessness and Remorse "Suppose, Brahmin, there is a bowl of water stirred by the wind, rippling, swirling, churned into wavelets. If a man with good sight were to examine his own facial reflection in it, he would neither know nor see it as it really is. So too, Brahmin, when one dwells with a mind obsessed by restlessness and remorse.”
Vicikiccha : Doubt 
"Suppose, Brahmin, there is a bowl of water that is turbid, unsettled, muddy, placed in the dark. If a man with good sight were to examine his own facial reflection in it, he would neither know nor see it as it really is. So too, Brahmin, when one dwells with a mind obsessed by doubt.”
Samadhi : Concentration "Suppose, Brahmin, there is a bowl of water that is not mixed with dyes; not bubbling and boiling; not covered over with water plants and algae; not stirred by the wind and churned into wavelets; clear, serene, limpid, set out in the light. If a man with good sight were to examine his own facial reflection in it, he would know and see it as it really is. So too, Brahmin, when one dwells with a mind that is not obsessed by sensual lust, ill will, dullness and drowsiness, restlessness and remorse, and doubt.”