Guna is a Sanskrit term and means quality, peculiarity, or tendency. A Guna is a tattva or element of reality that can affect our psychological, emotional, or energetic states.
The three Gunas are Sattva, Rajas, and Tamas.
i)Sattvic Guna is purity and Prakasam; it is a state of balance, harmony, joy, and intelligence. Sattva guna is a force favorable for the attainment of moksha. A sattvic mind is always steady and finds delight internally. The effect of sattva guna is Brahmavichara – inquiry into Brahman/ search for truth. Sattva is the guna that yogis achieve that reduces Tamas and Rajas and makes liberation possible. Sattvapatti is a state of mind wherein there is the purity of thought and purity of heart.
ii)Rajasic Guna is a hostile force to pull you down into samsara. Rajas is a state of energy, action, change, and movement. A sattvic mind will make a man still and inactive, while a Rajsic mind will make him restless. The Rajasic mind remembers the defects of others, and good/bad deeds, which intensifies hatred and disturbance in the mind. The nature of Rajas is attraction, longing, and attachment.
iii)Tamasic Guna is a state of darkness, ignorance, and delusion. If the natural rhythm of sleep and wakefulness is disturbed, Tamas is increased. Other tamasic qualities are laziness, disgust, attachment, depression, helplessness, doubt, guilt, shame, boredom, addiction, hurt, sadness, apathy, confusion, grief, dependency, and ignorance.