Hindrance. The mental qualities that hinder the mind from becoming centered are five: sensual desire, ill will, torpor & lethargy, restlessness & anxiety, and uncertainty.

niivara.na]: Hindrances to concentration — sensual desire, ill will, sloth & drowsiness, restlessness & anxiety, and uncertainty.

One of five 'hindrances' that obstruct the development of concentration and insight: sensual desire, ill will, sloth-and-torpor, restlessness and skeptical doubt. The scriptures compare them respectively to water mixed with colors, boiling water, water covered by moss, water whipped by wind, and muddy water.