Serenity of mind, good-heartedness, silence, self-control, purity of nature — these together are called the mental austerity.

manaḥprasādaḥ = satisfaction of the mind; saumyatvaṃ = being without duplicity towards others; maunaṃ = gravity; ātma = of the self; vinigrahaḥ = control; bhāva = of one’s nature; saṃśuddhiḥ = purification; iti = thus; etat = this; tapaḥ = austerity; mānasaṃ = of the mind; ucyate = is said to be.;