Shiva Purana

siva.sh/siva-purana/kotirudra-samhita/13/57

शिवाभ्यां स्थापिता यस्मात्तस्मात्तं वटुकाः स्मृताः ।। तपोभ्रष्टाश्च ये जाताः स्मृतास्तस्मात्तपोधमाः ।। ५७।।

sanskrit

Because they had been established by Śiva and Śivā they are known as Vaṭukas. Those who neglect penance are known as Tapodhamas.

english translation

zivAbhyAM sthApitA yasmAttasmAttaM vaTukAH smRtAH || tapobhraSTAzca ye jAtAH smRtAstasmAttapodhamAH || 57||

hk transliteration by Sanscript