1) Austerities. 2) The experience of heat that occurs during the process of practising yoga. The heat is generated by friction between the senses and renunciation. It is said that this heat, called "the fire of yoga," burns up all the impurities that lie between the seeker and the experience of the Truth.

Performing deep penance.

penance, asceticism

austerity; accepting some voluntary inconvenience for a higher purpose.

Austerity, asceticism or severe self-discipline.

effort, energism, austerity of the personal will, ascetic force, askesis; concentration of the will and energy to control the mind, vital and physical and to change them or to bring down the higher consciousness or for any other yogic purpose or high purpose.

Tapasya is the principle and practice of physical and spiritual austerity and discipline to achieve a particular aim.