Friends:

These are the 5 Mental Hindrances:

The Blessed Buddha once said:
Bhikkhus, there are these five kinds of Mental Hindrance. What five?

1: The Mental Hindrance of Desire for Sensing...
2: The Mental Hindrance of Aversion and Ill-Will...
3: The Mental Hindrance of Lethargy and Laziness…
4: The Mental Hindrance of Restlessness and Regret…
5: The Mental Hindrance of Doubt and Uncertainty…

These are the 5 kinds of Mental Hindrance! The Noble 8-fold Way should
be developed for the direct experience of these five Mental Hindrances,
for the full understanding and elimination of them, and for their final and
total overcoming, abandoning and leaving all behind! This Noble 8-fold Way
is developed for the sake of uprooting all Mental Hindrance!

Explanation of the 5 Mental Hindrances:
Desire for sights, sounds, smells, flavours, touches, & thoughts is obvious.
Aversion is hate, anger, irritation, opposition, resistance, & stubbornness.
Lethargy & Laziness are all sluggishness, indolence, slow and slack inactivity.
Restlessness & Regret are agitation, anxiety, hurry, remorse, and worry.
Doubt & Uncertainty are indecision, hesitation, perplexity, & qualm dilemma.
Mental Hindrance means a mental & invisible yet real & ultimately effective
obstacle, obstruction, block, impediment, hurdle and debilitating handicap!

For details on the Mental Hindrances – Nīvaraṇa and their removal:
http://What-Buddha-Said.net/Canon/Sutta/AN/AN.I.3-4.htm

More on  these 5 Mental Hindrances (Nīvaranas):
http://What-Buddha-Said.net/drops/II/The_Fire_of_Sense-Desire.htm
http://What-Buddha-Said.net/drops/II/Restlessness_and_Regret.htm
http://What-Buddha-Said.net/drops/II/Starving_the_Hindrances.htm
http://What-Buddha-Said.net/drops/II/Feeding_the_Hindrances.htm
http://What-Buddha-Said.net/drops/II/Doubt_and_Uncertainty.htm
http://What-Buddha-Said.net/drops/II/Lethargy_and_Laziness.htm
http://What-Buddha-Said.net/drops/IV/Suitable_Substitution.htm
http://What-Buddha-Said.net/drops/II/Colourful_but_Muddy.htm
http://What-Buddha-Said.net/drops/II/Anger_and_Irritation.htm
http://What-Buddha-Said.net/drops/II/How_5_Become_10.htm
http://What-Buddha-Said.net/drops/II/Naturally_Radiant.htm
http://What-Buddha-Said.net/Canon/Sutta/AN/AN.I.3-4c.htm
http://What-Buddha-Said.net/Canon/Sutta/AN/AN.I.3-4.htm
http://What-Buddha-Said.net/drops/II/The_Canal.htm

The unhindered and undefiled mind is calm and luminous!

Source (edited extract):
The Grouped Sayings of the Buddha. Samyutta Nikāya.
Book [V:60] section 45: The Way. 177: The 5 Mental Hindrances ...
http://www.pariyatti.com/book.cgi?prod_id=948507
http://www.accesstoinsight.org/canon/samyutta/index.html

Mental Hindrances!