The term ‘Anta’ means destruction or death. Yama is known as Antaka as he controls the death of all creatures. When Sāvitrī (Savatri), going to Yamaloka , prayed to Yama in order to get her husband’s life back, she addressed Yama as Antaka at that time.
sarveṣāmeva bhūtānāṃ yasmādantakaro mahān
tasmāt tvamantakaḥ proktaḥ sarvadevairmahādyute.
[See Yama]